Iron-modified biochar inhibiting Cd uptake in rice by Cd co-deposition with Fe oxides in the rice rhizosphere

Fe-enriched biochar has proven to be effective in reducing Cd uptake in rice plants by enhancing iron plaque formation. However, the effect of Fe on biochar, especially the biochar with high S content, for Cd immobilization in rice rhizosphere was not fully understood. To obtain eco-friendly Fe-loaded biochar at a low cost, garlic straw, bean straw, and rape straw were chosen as the feedstocks for Fe-enhanced biochar production by co-pyrolysis with Fe2O3. The resulting biochars and Fe-loaded biochars were GBC, BBC, BRE, GBC-Fe, BBC-Fe, and BRE-Fe, respectively. XRD and FTIR analyses showed that Fe was successfully loaded onto the biochar. The pristine and Fe-containing biochars were applied at rates of 0% (BC0) and 0.1% in pot experiments. Results suggested that BBC-Fe caused the highest reduction in Cd content of rice grain, and the reductions were 67.9% and 31.4%, compared with BC0 and BBC, respectively. Compared to BBC, BBC-Fe effectively reduced Cd uptake in rice roots by 47.5%. The exchangeable and acid-soluble fraction of Cd (F1-Cd) in soil with BBC-Fe treatment was 37.6% and 63.7% lower than that of BC0 and BBC, respectively. Compared to BC0, soil pH was increased by 0.53 units with BBC-Fe treatment. BBC-Fe significantly increased Fe oxides (free Fe oxides, amorphous Fe oxides, and complex Fe oxides) content in the soil as well. DGT study demonstrated that BBC-Fe could enhance the mobility of sulfate in the rhizosphere, which might be beneficial for Cd fixation in the rhizosphere. Moreover, BBC-Fe increased the relative abundance of Bacteroidota, Firmicutes, and Clostridia, which might be beneficial for Cd immobilization in the rhizosphere. This work highlights the synergistic effect of loaded Fe and biochar on Cd immobilization by enhancing Cd deposited with Fe oxides.

Roles of nanoparticles in arsenic mobility and microbial community composition in arsenic-enriched soils

Environmental effects of nano remediation engineering of arsenic (As) pollution need to be considered. In this study, the roles of Fe2O3 and TiO2 nanoparticles (NPs) on the microbial mediated As mobilization from As contaminated soil were investigated. The addition of Fe2O3 and TiO2 NPs restrained As(V) release, and stimulated As(III) release. As(V) concentration decreased by 94% and 93% after Fe2O3 addition, and decreased by 89% and 45% after TiO2 addition compared to the Biotic and Biotic+Acetate (amended with sodium acetate) controls, respectively. The maximum values of As(III) were 20.5 and 27.1 µg/L at 48 d after Fe2O3 and TiO2 NPs addition, respectively, and were higher than that in Biotic+Acetate control (12.9 µg/L). The released As co-precipitated with Fe in soils in the presence of Fe2O3 NPs, but adsorbed on TiO2 NPs in the presence of TiO2 NPs. Moreover, the addition of NPs amended with sodium acetate as the electron donor clearly promoted As(V) reduction induced by microbes. The NPs addition changed the relative abundance of soil bacterial community, while Proteobacteria (42.8%-70.4%), Planctomycetes (2.6%-14.3%), and Firmicutes (3.5%-25.4%) were the dominant microorganisms in soils. Several potential As/Fe reducing bacteria were related to Pseudomonas, Geobacter, Desulfuromonas, and Thiobacillus. The addition of Fe2O3 and TiO2 NPs induced to the decrease of arrA gene. The results indicated that the addition of NPs had a negative impact on soil microbial population in a long term. The findings offer a relatively comprehensive assessment of Fe2O3 and TiO2 NPs effects on As mobilization and soil bacterial communities.

Release of biochar-derived dissolved organic matter and the formation of chlorination disinfection by-products: Effects of pH and chlorine dosage

Transformation, fragmentation, dissolution, and oxidation of biochar are inevitable in the environment, which will undoubtedly accelerate the release of biochar-derived dissolved organic matter (BDOM) into various water bodies. In addition, biochar may affect disinfection by-products (DBPs) during water treatment and subsequent disinfection. In this study, biochars were derived at three selected pyrolysis temperatures (350 °C, 500 °C, and 650 °C) from rice husk, wheat straw, and shrimp shell, and BDOM was extracted from biochar-derived in artificial seawater and ultrapure water. The TOC analyzer results showed that the concentrations of three BDOM decreased with increasing pyrolysis temperature. The BDOM derived from rice husk biochar and wheat straw biochar in seawater was lower than that in ultrapure water, while that of shrimp shell biochar showed an opposite trend, being released in seawater at nearly twice the extent of that in ultrapure water at 350 °C. Moreover, BDOM showed a catalytic effect on chlorination, and GC analysis showed that the concentrations of its DBPs were affected by pH. The concentration of halogenated acetic acid reached the highest value (54.51 μg/L) in weak acidic environment, while the concentrations of trihalomethane and halogenated acetonitrile had the highest values (23.63 and 47.53 μg/L, respectively) in alkaline conditions. The concentrations of all the three DBPs were lowest under neutral pH conditions. In addition, the volatile halogenated DBPs such as dichloroacetone and trichloroacetone were easily hydrolyzed under alkaline conditions. Therefore, it is something be aware of the release of BDOM and the effects of chlorination DBPs when biochar is used for water treatment or water purification.

Potassium permanganate modification of hydrochar enhances sorption of Pb(II), Cu(II), and Cd(II)

Hydrochars formed by hydrothermal carbonization of hickory wood, bamboo, and wheat straw at 200 °C were modified by potassium permanganate (KMnO4) for the sorption of Pb(II), Cd(II), and Cu(II). The wheat straw hydrochar (WSHyC) modified with 0.2 M KMnO4 resulted in the most promising adsorbent (WSHyC-0.2KMnO4). Characterization of WSHyC and WSHyC-0.2KMnO4 revealed that the modified hydrochar features large specific surface area, rich of surface oxygenic functional groups (OCFG), and a significant amount of MnOx micro-particles. Batch adsorption experiments indicated that the adsorption rate by WSHyC-0.2KMnO4 was faster than for WSHyC, attaining equilibrium after around 5 h. The optimum adsorption capacity (Langmuir) of Pb(II), Cd(II), and Cu(II) by WSHyC-0.2KMnO4 was 189.24, 29.06 and 32.68 mg/g, respectively, 12 ∼ 17 times greater than by WSHyC. The significantly enhanced heavy metal adsorption can be attributable to the increased OCFG and MnOx microparticles on the surface, thereby promoting ion exchange, electrostatic interactions, and complexation mechanisms.

Pig manure biochar for contaminated soil management: nutrient release, toxic metal immobilization, and Chinese cabbage cultivation

Pig manure could be an effective fertilizer source for soil, but with high concentrations of xic elements. It has been shown that the pyrolysis method could largely reduce the environmental risk of pig manure. However, the comprehensive analysis of both toxic metals immobilization effect and environmental risk of pig manure biochar applied as a soil amendment is rarely addressed. To address the knowledge gap, this study was carried out with pig manure (PM) and pig manure biochar (PMB). The PM was pyrolyzed at 450 ℃ and 700 ℃, the corresponding biochar was abbreviated as PMB450 and PMB700, respectively. The PM and PMB were applied in a pot experiment growing Chinese cabbage (Brassica rape L. ssp. Pekinensis) with clay-loam paddy soil. The application rates of PM were set at 0.5% (S), 2% (L), 4% (M) and 6% (H). With the equivalent mass principle, PMB450 and PMB700 were applied at 0.23% (S), 0.92% (L), 1.84% (M), 2.76% (H), and 0.192% (S), 0.7% (L), 1.4% (M), 2.1% (H), respectively. Parameters of Chinese cabbage biomass and quality, total and available concentrations of toxic metals in soil, and soil chemical properties were systemically measured. The main results of this study showed that compared with PM, PMB700 was more effective than PMB450, which induced the highest reductions of Cu, Zn, Pb, and Cd contents in cabbage by 62.6%, 73.0%, 43.9%, and 74.3%, respectively. Both PM and PMB increased the total contents of metals (Cu, Zn, Pb, and Cd) in soil, and PMB decreased the mobility of Cu, Zn, Pb, and Cd at high application rates (≥2%). Treatment with H-PMB700 reduced CaCl₂ extractable Cu, Zn, Pb, and Cd by 70.0%, 71.6%, 23.3%, and 15.9%, respectively. For Cu, Zn, Pb, and Cd fractions with BCR extraction, PMB treatments, especially PMB700, were more effective than PM in decreasing the available fractions (F1 +F2 +F3) at high application rates (≥2%). Overall, pyrolysis with high temperature (e.g., 700 ℃) could significantly stabilize the toxic elements in PM and enhance PM's effect on toxic metals immobilization. The marked effects of PMB700 on toxic metal immobilization and cabbage quality improvement might be attributed to high ash contents and liming effect.

Mechanochemical modified nitrogen-rich biochar derived from shrimp shell: Dominant mechanism in pyridinic-N for aquatic methylene blue removal

N-doping for the preparation of functional carbon materials is a trending research topic. In this study, N-rich biochar (BC) was prepared by calcining naturally N rich shrimp shells under oxygen-limiting environment, and the calcining temperatures were controlled. BC were activated with 5% hydrochloric acid solutions and then post-modified with ball-milling to obtain a series of novel adsorbents (MBCs). All samples were characterized by SEM, BET, FT-IR, XRD, XPS, TG, and element analysis. Surface area, pore volume, and other surface functional groups were significantly improved after acidizing and ball-milling. The adsorption capacities for MB were MBC350 > MBC500 > MBC650 >BC350 > BC650 > BC500, and the equilibrium adsorption capacities were 575.01 mg/g, 506.52 mg/g, 424.59 mg/g, 113.31 mg/g, 93.53 mg/g and 86.25 mg/g, respectively. The excellent adsorption performance of MBCs for MB was ascribed to Lewis acid-base interaction, π-π interaction, electrostatic interaction and van der Waals, and the quinone group and pyridinic-N on the surface of the MBCs are identified as the major active sites. Taken together, ball-milled shrimp shell biochar is a promising material for cation dye adsorption.

Effect of hydrodynamics on the transformation of nitrogen in river water by regulating the mass transfer performance of dissolved oxygen in biofilm

Biofilms drive crucial ecosystem processes in rivers. This study provided the basis for overall quantitative calculations about the contribution of biofilms to the nitrogen cycle. At the early stage of biofilm formation, dissolved oxygen (DO) could penetrate the biofilms. As the biofilm grew and the thickness increased, then the mass transfer of DO was restricted. The microaerobic layer firstly appeared in biofilm under the turbulent flow conditions, with the appearance of the microaerobic and anaerobic layer, the nitrification and denitrification reaction could proceed smoothly in biofilm. And the removal efficiency of total nitrogen (TN) increased as the biofilm matured. Under the turbulent flow conditions, mature biofilms had the smallest thickness, but the highest proportion the anaerobic layer to the biofilm thickness, the highest density, and the highest nitrogen removal efficiency. However, the nitrogen removal efficiency of biofilm was the lowest under laminar flow conditions. The difference of layered structure of biofilm and the DO flux in biofilm explained the difference of nitrogen migration and transformation in river water under different hydrodynamic conditions. This study would help control the growth of biofilm and improve the nitrogen removal capacity of biofilm by regulating hydrodynamic conditions.

Visible-light-assisted persulfate activation by SnS2/MIL-88B(Fe) Z-scheme heterojunction for enhanced degradation of ibuprofen

Herein, a highly efficient Z-scheme SnS₂/MIL-88B (Fe) (SnSFe) heterojunction was successfully synthesized to use both as photocatalysts and persulfate (PS) activator for ibuprofen (IBP) degradation. Flower-liked SnS₂ was uniformly loaded on MIL-88B (Fe), and SnSFe retained the original polyhedral morphology of MIL-88B (Fe). The highest removal of IBP was achieved in the presence of SnSFe with 0.5% SnS₂(SnSFe0.5). Characteristic results and density functional theory calculations demonstrated that the enhanced degradation of IBP was due to the difference in Fermi energy levels of SnS₂ and MIL-88B (Fe) leading to electrons transferred from SnS₂ to MIL-88B (Fe), and SnO bond was formed in SnSFe. , OH and O₂^- were the main active species in SnSFe0.5/PS/visible light system. Z-scheme heterojunction of SnSFe was constructed to propose the degradation mechanism. This research revealed that the synergism of photocatalysis and PS activation using SnS₂/Fe-based MOFs composites possessed great potentials in wastewater remediation.

Microwave-assisted pyrolysis derived biochar for volatile organic compounds treatment: Characteristics and adsorption performance

Biochar derived from corn stalk doping with activated carbon was produced by microwave-assisted pyrolysis and applied to sorb volatile organic compounds (VOCs: benzene and o-xylene). Specific surface area (SSA), total pore volume (TPV) and micropore volume (MV) of microwave biochar increased with increasing microwave power with the maximum values 325.2 m²·g^-1, 0.181 mL·g^-1 and 0.1420 mL·g^-1, respectively. Adsorption capacities of benzene and o-xylene on microwave biochar ranged 6.82-54.75 mg·g^-1 and 7.43-48.73 mg·g^-1, which were separate positively related with SSA, TPV, and MV. Benzene adsorption was mainly dominated by surface interaction and partition mechanisms, while o-xylene adsorption was governed by pore filling. The adsorption capacities of microwave biochar for benzene and o-xylene decreased by only 0.30% and 0.99% on the 5th cycle that illustrated the reasonably good reusability of microwave biochar. The results of this research demonstrate that microwave biochar is a promising adsorbent for VOCs removal.

Bimetallic FeNi nanoparticles immobilized by biomass-derived hierarchically porous carbon for efficient removal of Cr(VI) from aqueous solution

Nano zero-valent iron (nZVI) is an effective material for Cr(VI) treatment, however excessive agglomeration and surface oxidation limit its application. Herein, straw derived hierarchically porous carbon supported FeNi bimetallic nanoparticles (FeNi@HPC) was prepared for effective removal of Cr(VI) from water. FeNi nanoparticles were successfully loaded onto HPC with good dispersibility, and HPC caused an increase in specific surface area of FeNi nanoparticles. FeNi@HPC exhibited a significantly enhanced removal efficiency for Cr(VI) in comparison to Fe@HPC and FeNi NPs. The Ni doping content was further optimized, and the best Ni content in bimetallic NPs was estimated as 10 wt%. The conditions optimal for the activity of FeNi@HPC were assessed, and the highest removal efficiency equivalent to 30 mg L^-1 of Cr(VI) was achieved at pH= 4.0 in 360 min with a dosage of 0.5 g L^-1. Higher temperatures favored the removal of Cr(VI) and FeNi@HPC manifested the lowest activation energy as compared to Fe@HPC and FeNi NPs. The action mechanisms of FeNi@HPC presumably involved electron transfer from Fe⁰, Fe²⁺and atomic hydrogen. This work not only provide a cost-effective and available HPC material to stabilize nZVI but also revealed that using FeNi@HPC is a promising approach for the remediation of water pollution.

Carbothermal Synthesis of Ni/Fe Bimetallic Nanoparticles Embedded into Graphitized Carbon for Efficient Removal of Chlorophenol

The reactivity of nanoscale zero-valent iron is limited by surface passivation and particle agglomeration. Here, Ni/Fe bimetallic nanoparticles embedded into graphitized carbon (NiFe@GC) were prepared from Ni/Fe bimetallic complex through a carbothermal reduction treatment. The Ni/Fe nanoparticles were uniformly distributed in the GC matrix with controllable particle sizes, and NiFe@GC exhibited a larger specific surface area than unsupported nanoscale zero-valent iron/nickel (FeNi NPs). The XRD results revealed that Ni/Fe bimetallic nanoparticles embedded into graphitized carbon were protected from oxidization. The NiFe@GC performed excellently in 2,4,6-trichlorophenol (TCP) removal from an aqueous solution. The removal efficiency of TCP for NiFe@GC-50 was more than twice that of FeNi nanoparticles, and the removal efficiency of TCP increased from 78.5% to 94.1% when the Ni/Fe molar ratio increased from 0 to 50%. The removal efficiency of TCP by NiFe@GC-50 can maintain 76.8% after 10 days of aging, much higher than that of FeNi NPs (29.6%). The higher performance of NiFe@GC should be ascribed to the significant synergistic effect of the combination of NiFe bimetallic nanoparticles and GC. In the presence of Ni, atomic H* generated by zero-valent iron corrosion can accelerate TCP removal. The GC coated on the surface of Ni/Fe bimetallic nanoparticles can protect them from oxidation and deactivation.

Sorption behavior of dimethyl phthalate in biochar-soil composites: Implications for the transport of phthalate esters in long-term biochar amended soils

The characteristics and content of organo-mineral complex were confirmed to be changed in agriculture soils under the biochar application with long-term, but the resulting environmental effects in the retention and lasting of agrochemicals and xenobiotic pollutants is far from clear. In this study, biochar-soil composites were prepared by one-step dry ball-milling method, and a sorption case study was proceed to investigate the biochar incorporated affection in soils on the transport of dimethyl phthalate (DMP). More surface oxygen-containing functional groups on ball-milled biochar enhanced its complexation with soil minerals. Sorption isotherms of DMP onto the biochar-soil composites were well described by the Freundlich model, both heterogeneous surface and multilayer interactions occurred simultaneously. The kinetics of sorption could be simulated with the pseudo-second-order model (R² > 0.98), while the average sorption energy (E_a) calculated from Dubinin-Radushkevich isotherms were found in the range of 3.83-5.60 kJ mol^-1, which revealed that the sorption processes coexist of chemisorption and physisorption, and π-π electron donor-acceptor interaction, pore-filling and hydrophobic interactions could be identified as the main sorption mechanisms. Desorption of absorbed DMP appeared obvious nonlinear characteristics and lag effect, the calculated hysteresis index (HI) increased with the application of biochar into soil. Considering the phenomenon of biochar aging and soil complexation, it is important to verify how the transport and natural attenuation of contaminant will be influenced by biochar addition, especially the long-term effect in soil ecosystem.

Simulated photocatalytic aging of biochar in soil ecosystem: Insight into organic carbon release, surface physicochemical properties and cadmium sorption

Photochemical/photocatalytic reaction, one of the aging pathway of biochar in soil, not only changed the physicochemical properties of biochar, but also affected the migration and transformation of pollutants. Wheat straw biochar was photocatalytic aged in a Fenton-like system using organic acid as buffer solution under light sources, the organic carbon release and surface chemical changes of biochar were investigated to illustrate the adsorption behaviors. With Fe(III) or α-Fe₂O₃ added, the total organic carbon (TOC) of aged biochar solution was influenced more by buffer system than light sources, with the highest of 420.59 mg L^-1 in citric acid system. The production of the hydroxyl radical (OH·) at citric/Fe(III) system was higher than the oxalic/Fe(III) system under the Hg lamp and showed an increasing trend with time. With light exposure, the porous structure of the biochar altered and surface area increased from 7.613 to 29.74 m² g^-1. Meanwhile, the adsorption of cadmium ion by biochar aged in citric/Fe(III) system also showed an increased adsorption capacity with a maximum of 73.54 mg g^-1. So, a well understanding of biochar physicochemical properties changes under natural ecosystem was undoubtedly useful for scientific assessment the long-term feasibility of biochar as soil remediation.

Insights into the effects of long-term biochar loading on water-soluble organic matter in soil: Implications for the vertical co-migration of heavy metals

Although interest in biochar remediation is growing, the effects of long-term biochar loading on soil environments have not been clearly confirmed. The contents and characteristics of water-soluble organic matter (WSOM) from soils after eight years of biochar remediation were investigated, and the vertical co-migration of heavy metals controlled by interactions between WSOM, soil and contaminants were also analyzed. The results showed that biochar-leaching WSOM featured high aromaticity. Fluorescence excitation-emission matrix (EEM) spectrophotometry was employed, and three primary components, including fulvic-acid-like (FA_-like), tryptophan, and humic-acid-like (HA_-like) compounds, were identified in the EEM spectra via parallel factor analysis models. With increasing biochar loading, FA_-like and HA_-like greatly increased, but tryptophan showed a weak response. Furthermore, the WSOM was freeze dried and analyzed with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, and the results demonstrated that the BC treatment increased oxygen-containing functional groups and enhanced the complexation capability of the WSOM. Finally, the Cd and Pb concentrations in the WSOM were investigated, and Cd was found to decrease in top-soil WSOM with added BC because of increased complexation, but the Pb content increased because exchangeable and carbonate Pb converted into organic Pb. Further, the Cd and Pb concentrations decreased in sub-soil WSOM. These findings suggest that more efforts should be devoted to studying the effects of long-term biochar loading on soil environments.

Tobacco control in China and the road to Healthy China 2030

Healthy China 2030 aims to reduce the adult smoking rate from 27.7% in 2015 to 20% by 2030. Achieving this goal requires a review of the tobacco control measures introduced in China to date, the gaps that remain and the opportunities ahead. In 2008, the World Health Organization introduced six measures to reduce demand for tobacco called MPOWER. The progress China has made in implementing these measure varies: 1) monitor tobacco use and prevention policies. The surveillance on tobacco use has been rigorous, but the monitoring and evaluation of tobacco control policies needs to be strengthened; 2) protect people from tobacco use: pushes for national tobacco control legislation have stalled, but 18 subnational legislations have passed; 3) offer help to quit tobacco use. The accessibility and quality of cessation services needs to be improved; 4) warn about the dangers of tobacco. While there are no pictorial health warnings, tobacco control advocates have launched a series of anti-smoking media campaigns to inform the public; 5) enforce bans on tobacco advertising, promotion, and sponsorship. Legal loopholes and poor enforcement remain challenges; 6) raise taxes on tobacco: cigarettes in China are relatively cheap and increasingly affordable, which demonstrates the need for further tobacco tax increases indexed to inflation and income. China maintains a tobacco monopoly that interferes with tobacco control efforts and fails to regulate tobacco products from the public health perspective. Effective MPOWER measures, which depend upon the removal of tobacco industry interference from policymaking, are key to achieving the goal set by Healthy China 2030.

Characteristics of organo-mineral complexes in contaminated soils with long-term biochar application

Long-term studies on the environmental effects following biochar additions to soils, while plentiful, are predominantly focused on the soil fertility, whereas few are on the soil organo-mineral complexes. This study examines the changes of organo-mineral complexes in an acidic paddy soil and a saline-alkali soil which were remediated using biochar for approximately 8 years and 3 years, respectively. The results showed that loosely combined humus increased by 30.1% and 25.1% with the application of 40 t ha^-1 biochar in the acidic paddy soil and the saline-alkali soil, respectively. Meanwhile, an increase of cement (Fe-oxides) was the contributor to the rise of the complexes content. Complex iron in the saline-alkali soil were 30% higher than in the acidic paddy soil with the application of 40 t ha^-1 biochar. Fourier Transform Infrared Spectroscopy showed oxygen-containing functional groups on the surface of the biochar separated from the remediated field. X-ray diffraction analysis indicated that both complexation and sedimentation were involved in heavy metal immobilization. It was found that biochar amendment mitigated the effect of acid rain leaching and reduced vertical migration of the Fe/Al-bound complex, which can prevent soil from podzolization and thus improve its fertility.

Effects of laboratory biotic aging on the characteristics of biochar and its water-soluble organic products

Effects of biotic aging on the characteristics of biochar and its water-soluble organic products were determined through a one-year laboratory incubation study. Biochar had a positive influence on microbial population size. Without microbial addition, biochars showed little change, except for an obvious increase in oxygen content from 3.2% to 6.3% after one year. By contrast, the carbon (C) content of the biologically-aged biochars continually decreased throughout the incubation at two humidity levels, suggesting that microbes consumed biochar C or encouraged organic matter solubilization. Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated that all aged biochar surfaces showed increases in oxygen-containing functional groups and TG-DTG analysis showed that biologically-aged biochars were less stable than the corresponding abiotically-aged one. The release of dissolved organic matters from biologically-aged biochar logarithmically increasing with time, corresponded with of the pattern of microbe production, suggesting microbial involvement in solubilizing biochar. Combined three-dimensional excitation-emission matrix (3DEEM) and parallel factor (PARAFAC) analyses revealed that fulvic and humic acid-like components were the main water-soluble products of biologically-aged biochar, and these became increasingly rich in O-containing functional groups, i.e. humified, over time. These results highlight the importance of microbes in chemically transforming biochar and the dissolved products of biochar during aging.

Adsorptive and Reductive Removal of Chlorophenol from Wastewater by Biomass-Derived Mesoporous Carbon-Supported Sulfide Nanoscale Zerovalent Iron

Chlorinated compounds in a water environment pose serious threats to humanity. A nanoscale zerovalent iron (nZVI) has desirable properties for water dichlorination, but its reactivity is still limited by agglomeration and oxidation. In this study, the mesoporous carbon (MC) derived from biomass waste was prepared for immobilizing nZVI, and the nZVI@MC was further modified by sulfur (S-nZVI@MC) to relieve surface oxidation. The synergistic effect between nZVI and surface modification, the reaction conditions and the removal mechanism were investigated systematically. The characterization results showed nZVI was successfully loaded on the surface of MC, and the aggregation of nZVI was prevented. Moreover, sulfidation modification resulted in the formation of FeS on the surface of nZVI, which effectively alleviated surface oxidation of nZVI and promoted the electron transfer. Batch experiments demonstrated S-nZVI@MC had greatly enhanced reactivity towards 2,4,6-trichlorphenol (TCP) as compared to MC and nZVI, and the removal rate could reach 100%, which was mainly attributed to the significant synergistic effect of MC immobilization and sulfidation modification. Furthermore, the TCP removal process was well described by a Langmuir adsorption model and pseudo-second-order model. The possible mechanism for enhanced removal of TCP is the fast adsorption onto S-nZVI@MC and effective reduction by S-nZVI. Therefore, with excellent reducing activity and antioxidation, S-nZVI@MC has the potential as a pollutant treatment.

Environmental occurrences, fate, and impacts of microplastics

Microplastics (MPs) are small plastic pieces with size less than 5 mm that have entered and polluted the environment. While many investigations including several critical reviews on MPs in the environment have been conducted, most of them are focused on their occurrences in marine environment. Current understanding on the occurrences, behaviors, and impacts of MPs in the terrestrial environment is far from complete. A systematic review of the literature was thus conducted to promote the research on MPs in the environment. This work is designed to provide a comprehensive overview that summarizes current knowledge and research findings on environmental occurrences, fate and transport, and impacts of MPs. In addition to discussing the occurrences, characteristics, and sources of MPs in the ocean, freshwater, sediments, soils, and atmosphere, the review also summarizes both the experimental and modeling data of the environmental fate and transport of MPs. Research findings on the toxic effects, bioaccumulation, and bioavailability of MPs in the environment are also covered in this critical review. Future perspectives are discussed as well.

Biochar Immobilizes and Degrades 2,4,6-Trichlorophenol in Soils

Soil contamination by chlorophenol compounds, such as 2,4,6-trichlorophenol (2,4,6-TCP), is of great concern because they are environmentally persistent, are difficult to degrade, and can lead to cancer. Thus, means of degrading these compounds in situ are desperately needed. Biochar was investigated as a material to sequester, reduce downward transport, and aid in soil 2,4,6-TCP degradation. In 2 column studies, wheat straw (Triticum aestivum L.)-derived biochar (pyrolyzed at 450 °C) application to soil (up to 5% by wt) improved soil water and soil organic carbon content. Biochar reduced 2,4,6-TCP downward transport, likely attributable to improved soil water mobility and retention, allowing 2,4,6-TCP to be more easily transported and sorbed to organic functional groups on biochar, leading to enhanced degradation. The 2,4,6-TCP was rapidly degraded into a combination of benzene derivatives and low-molecular weight organic compounds in the first 2 mo following biochar application. The present study provides evidence that biochars can be used to improve environmental quality by lessening the downward transport and enhancing the degradation of organochlorine compounds such as 2,4,6-TCP. Environ Toxicol Chem 2019;38:1364-1371. © 2019 SETAC.

Colorimetric Determination of Hypochlorite Based on the Oxidative Leaching of Gold Nanorods

Hypochlorite plays a critical role in killing microorganisms in the water. However, it can also cause cardiovascular diseases, neuron degeneration, and cancer to humans. Although traditional methods feature excellent sensitivity and reliability in detecting hypochlorite, the expensive instruments and strict determination conditions have limited their application in environmental analysis to some extent. Thus, it is necessary and urgent to propose a cheap, facile, and quick analytical assay for hypochlorite. This paper proposes a colorimetric assay for hypochlorite utilizing gold nanorods (AuNRs) as the nanoreactor and color reader. The AuNRs were acquired via a reported seed-mediated method. NaClO with strong oxidation property can cause the etching of gold from the longitudinal tips of AuNRs, which could shorten the aspect ratio of AuNRs, decrease the absorption in the UV–Vis spectrum and also induce the solution color changing from red to pale yellow. Thus, according to the solution color change and the absorbance of longitudinal surface plasmon resonance of AuNRs, we established the calibration curve of NaClO within 0.08 μM to 125 μM (∆Abs = 0.0547 + 0.004 C_NaClO, R² = 0.9631). Compared to traditional method, we obtained the conversion formula between the concentration of residual-chlorine in tap water and the concentration of hypochlorite detected by the proposed colorimetric assay, which is C_{residual-chlorine} = 0.24 C_NaClO. Finally, the real application of the colorimetric assay in tap water was successfully performed, and the accuracy of the colorimetric method can reach from −6.78% to +8.53%.

Effects of chemical oxidation on surface oxygen-containing functional groups and adsorption behavior of biochar

Biochar is a beneficial soil amendment but the changes in its surface properties during the aging process, especially the oxygen-containing functional groups and the associated adsorption behaviors, are not well documented. In this paper, the aged wheat straw biochar was simulated by chemical oxidation with HNO₃-H₂SO₄ and NaOH-H₂O₂ systems. Characterization results showed that carbon loss and oxygen incorporation ran throughout the aging process. Surface oxygen-containing functional groups were found to be increased in all treated biochars, especially for carboxyl. Much more developed mesopores were observed in aging biochar, specific surface area was increased by 126% for biochar treated with NaOH-H₂O₂, and 226% for biochar treated with 40% of HNO₃-H₂SO₄. Thermogravimetric analysis showed that the increasing oxygen-containing functional groups led to 14% and 30% mass loss by treating biochar with alkali and acid, respectively. The improved biochar surface through the increase of oxygen-containing functional groups enhanced the cadmium sorption capacity, and the sorption capacity increased by 21.2% in maximum. Roughed surface from oxidation was another reason for increasing cadmium adsorption. Results indicated that the adsorption performance of biochar on pollutant would be changed during aging process along with the changing surface properties.

Facile Synthesis of Magnetic Nitrogen-Doped Porous Carbon from Bimetallic Metal⁻Organic Frameworks for Efficient Norfloxacin Removal

Magnetic nitrogen-doped porous carbon (MNPC) has been prepared via self-catalytic pyrolysis of bimetallic metal-organic frameworks (MOFs). The as-obtained MNPC showed favorable features for antibiotics adsorption such as high specific surface area (871 m² g-1), high pore volume (0.75 cm³ g-1), porous structure, good graphitization degree, and rich N-doping. Moreover, the MNPC has magnetic properties due to the Co species, which is embedded with a high dispersion, so the absorbent can be easily separated. Based on the above excellent characteristics, the MNPC was used as the absorbent for norfloxacin (NOR) removal. The experimental maximum NOR adsorption capacity of MNPC was 55.12 mg g-1 at 298.15 K and a pH of 6.0 with an initial NOR concentration of 50 mg L-1. The data analysis of the kinetics revealed that the experimental data of NOR uptakes versus time agreed with the pseudo-second order model. The isotherm data analysis revealed the favorable application of the Freundlich model. Based on the adsorption results over a wide range of conditions, the dominant adsorption mechanisms were found to be pore-filling, electrostatic interaction, and the H-bond.

Enhanced hydrogen adsorption on graphene by manganese and manganese vanadium alloy decoration

In this work, two kinds of novel manganese decorated (G + Mn) and manganese-vanadium co-decorated (G + MnV) graphene composites are synthesized by in situ wet chemical reduction, and their hydrogen storage properties and microstructures are characterized by Sievert-type adsorption apparatus, BET, SEM, TEM/STEM, EDX and EELS. Compared with pristine graphene, Mn decoration marginally increases the hydrogen adsorption capacity of graphene at room temperature and 4 MPa hydrogen pressure from 0.25 wt% to 0.36 wt%. On the other hand, the co-decoration of Mn and V increases the room temperature hydrogen storage capacity of graphene significantly to 1.81 wt% under 4 MPa hydrogen pressure, which is 1.56 wt% higher than the capacity of pristine graphene. The microstructures and valence states of the decorated Mn and Mn-V nanoparticles are investigated by TEM, EDX and EELS analyses, and strong interactions between the decorated nanoparticles and graphene are observed. Based on the results from structural analyses, potential enhancement mechanisms are suggested in terms of the catalytic effects of nanoparticles on graphene hydrogen adsorption. Given the relatively low cost of Mn and V metals compared to noble metals such as Pd, Pt and Au, these results demonstrate a low cost and effective way to significantly enhance the room temperature hydrogen adsorption properties of graphene for potential hydrogen storage applications.

Facile synthesis of novel hierarchically porous carbon derived from nature biomass for enhanced removal of NaCl

In this work, the hierarchically porous biomass carbon (HPBC) was originally prepared for desalination through a simple activation of cheap biomass carbon (BC). Such crucial activated conditions as the KOH/C ratio, the activation time and the activation temperature were deeply investigated. It is demonstrated that the activated conditions had a great influence on the structure properties and electrochemical performance. According to structure and surface analyses, the HPBC with larger surface area and hierarchical porous structure could be well obtained in suitable activation conditions. The electrochemical analyses showed that the HPBC showed increased electrosorption capacitance, lower inner resistance and good stability, which can be attributed to large accessible surface area and smooth ion transportation. In the further desalination test, the HPBC electrode exhibited enhanced desalination efficiency and capacity. Hence, HPBC can be a promising candidate electrode material for desalination with low cost and high efficiency.

Degradation of Herbicide Mesotrione in Three Soils with Differing Physicochemical Properties from China

The movement and fate of herbicides in soils under various environmental factors are important in evaluating their mobility and ecological impact. The effects of sterilization, solarization, and soil physicochemical properties on the degradation of herbicide mesotrione in three soils from China were evaluated using laboratory incubation method, and the degradation kinetics were also simulated using pseudo first-order reaction model. The calculated half-lives () of mesotrione were found to be 3.78- to 5.24-fold increased in sterilized soils than nonsterilized soils, which indicated that the degradation of mesotrione was strongly affected by soil microbial activity. A certain role of promoting degradation effect of natural light was found, and the values appeared to be only 7.90, 15.89, and 25.29 d in the surface of paddy soil, sandy loess, and silt clay loam, respectively. Correlation analysis between the observed first-order reaction rate constant () values and the selected soil properties revealed that the degradation of mesotrione was highly dependent on soil pH value ( > 0.992) and organic matter content ( > 0.932), but less related with clay content (<0.02 mm) with < 0.761 and nonrelated with cation exchange capacity (CEC) ( < 0.164). Data obtained in this study are helpful for further research on the prediction of the movement and fate of mesotrione in soils in limiting its environmental impact.

Catalytic Roles of Mn(II) and Fe(III) in the Reduction of Cr(VI) by Mandelic Acid under an Irradiation of Simulated Solar Light

The catalytic roles of manganese(II) [Mn(II)] and iron(III) [Fe(III)] in the reduction of hexavalent chromium [Cr(VI)] by mandelic acid, both with and without the presence of light, was investigated through a series of batch experiments. The results demonstrated that both Mn(II) and Fe(III) could markedly accelerate the photoreduction of Cr(VI) by mandelic acid; additionally, the catalysis of Fe(III) was superior to that of Mn(II). Without the presence of light, Mn(II) still enhanced the reduction of Cr(VI) by mandelic acid, but Fe(III) did not exert any impact on the reaction. When compared with the activities of phenylacetic acid, it was concluded that the catalytic roles of both Mn(II) and Fe(III) in the reduction of Cr(VI) were directly related to the α-OH group and not to the carboxyl group. The photoreduction of Cr(VI) by mandelic acid, assisted by Mn(II), followed pseudo-first-order kinetics at the initial stage of the reaction, but in the presence of Fe(III) it followed a pseudo-zero-order model.

Adsorption, immobilization, and activity of beta-glucosidase on different soil colloids

For a better understanding of enzyme stabilization and the subsequent catalytic process in a soil environment, the adsorption, immobilization, and activity of beta-glucosidase on various soil colloids from a paddy soil were studied. The calculated parameters maximum adsorption capacity (q(0)) for fine soil colloids ranged from 169.6 to 203.7 microg mg(-1), which was higher than coarse soil colloids in the range of 81.0-94.6 microg mg(-1), but the lower adsorption affinity (K(L)) was found on fine soil colloids. The percentages of beta-glucosidase desorbed from external surfaces of the coarse soil colloids (27.6-28.5%) were higher than those from the fine soil colloids (17.5-20.2%). Beta-glucosidase immobilized on the coarse inorganic and organic soil colloids retained 72.4% and 69.8% of activity, respectively, which indicated the facilitated effect of soil organic matter in the inhibition of enzyme activity. The residual activity for the fine soil clay is 79-81%. After 30 days of storage at 40 degrees C the free beta-glucosidase retained 66.2% of its initial activity, whereas the soil colloidal particle-immobilized enzyme retained 77.1-82.4% of its activity. The half-lives of free beta-glucosidase appeared to be 95.9 and 50.4 days at 25 and 40 degrees C. Immobilization of beta-glucosidase on various soil colloids enhanced the thermal stability at all temperatures, and the thermal stability was greatly affected by the affinity between the beta-glucosidase molecules and the surface of soil colloidal particles. Due to the protective effect of supports, soil colloidal particle-immobilized enzymes were less sensitive to pH and temperature changes than free enzymes. Data obtained in this study are helpful for further research on the enzymatic mechanisms in carbon cycling and soil carbon storage.

Sera from patients with toxic epidermal necrolysis contain autoantibodies to periplakin

BACKGROUND

The pathophysiological mechanism of toxic epidermal necrolysis (TEN) with extensive bullae that is induced suddenly by drugs is not well understood. The individual patterns and distribution of the widespread mucocutaneous reactions of TEN often show striking similarities with those of paraneoplastic pemphigus (PNP), which is known to involve autoantibodies (aAbs) to members of the plakin family.

OBJECTIVES

To investigate the existence of circulating aAbs to periplakin in the sera of patients with TEN.

METHODS

The presence of circulating aAbs to periplakin was examined using immunoblotting, immunoabsorption and indirect immunofluorescence (IF) analyses. Recombinant protein expression was used to determine the interaction between periplakin and aAbs in the sera of patients with TEN.

RESULTS

Indirect IF studies revealed circulating aAbs in the intercellular area in the epidermis. Interestingly, on rat bladder the staining pattern of the IgG deposits was similar to that observed in patients with PNP. Immunoblotting analysis of the epidermal extracts was used to identify the aAbs in the sera of patients with TEN. These contained circulating aAbs to a 190-kDa protein corresponding to periplakin. Recombinant periplakin and domains of periplakin were prepared in order to confirm the existence of aAbs to periplakin. Immunoblotting with these proteins demonstrated that the sera from patients with TEN reacted with each domain as well as with the full-length periplakin.

CONCLUSIONS

We found that circulating aAbs in the sera of patients with TEN target periplakin. These aAbs might play a role in the pathogenesis of TEN as a humoral autoimmune mechanism.

Important causes of hypoglycaemia in patients with diabetes on peritoneal dialysis

AIM

Diabetes is now the commonest cause of end-stage renal failure, so there are many diabetic patients receiving dialysis therapy. There are several important ways in which dialysis practice can impinge unfavourably on glucose control. This study focuses on the interaction between maltose-derived metabolites in a new peritoneal dialysis fluid and blood glucose measurements using reagent sticks that depend on the glucose dehydrogenase method.

CASE REPORT

We report the cases of three patients, with insulin-treated diabetes and end-stage renal disease treated with peritoneal dialysis, who experienced symptomatic hypoglycaemia with inaccurate glucose readings on reagent strips when converted to icodextrin.

CONCLUSION

Careful teamwork between diabetes and renal physicians and specialist nurses is highly desirable to achieve good glucose control in a group of patients at particular risk of microvascular and macrovascular complications.

The effect of T-2 toxin on IL-1beta and IL-6 secretion in human fetal chondrocytes

The effects of T-2 toxin on IL-1beta and IL-6 secretion in human fetal chondrocytes in vitro were investigated. The evaluation is realised on primary monolayer culture of human fetal epiphyseal chondrocytes with or without PMA stimulation. The levels of supernatant IL-1beta and IL-6 were analyzed by ELISA. As compared with their respective controls, we observed a significant increase of IL-Ibeta and IL-6 in supernatants of chondrocytes cultivated for 24 h with T-2 at 8 ng/ml after PMA stimulation; in the absence of PMA, IL-Ibeta was increased alone after 48 h. The results demonstrated that T-2 toxin could superinduce IL-1beta and IL-6 secretion in chondrocytes. All these data suggested that superinduction of cytokines might be one of the key mechanisms of chondrocyte injuries by T-2 toxin.

Ki-ras mutation and p53 overexpression predict the clinical behavior of colorectal cancer: a Southwest Oncology Group study

We assessed Ki-ras mutations by single-strand conformation polymorphism followed by DNA sequencing, p53 expression by immunohistochemistry, ploidy status, and S-phase fraction in 66 stage II and 163 stage III colon cancer patients enrolled on a randomized trial of surgery followed by observation or adjuvant levamisole or 5-fluorouracil (5FU) plus levamisole (Intergroup Trial 0035) to see whether these factors were independently associated with survival or with differential effects of adjuvant therapy. A Cox proportional hazards survival model was used to describe marker effects and therapy by marker interactions, with adjustment for the clinical covariates affecting survival. A Bonferroni adjustment was used to account for multiple testing. Mutation of the Ki-ras gene was found in 41% of the cancers and was associated with a poor prognosis in stage II but not stage III. In stage II, 7-year survival was 86% versus 58% in those with wild type versus Ki-ras mutations. After adjustment for treatment and clinical variables, the hazard ratio (HR) for death was 4.5; 95% confidence interval (CI), 1.7-12.1 (P = 0.012). p53 overexpression was found in 63% of cancers and was associated with a favorable survival in stage III but not stage II. Seven-year survival in stage III was 56% with p53 overexpression versus 43% with no p53 expression (HR, 2.2; 95% CI, 1.3-3.6; P = 0.012). Aneuploidy was more common in stage III than in stage II (66 versus 47%; P = 0.009) but was not independently related to survival in either group. The proliferative rate was greater in aneuploid than in diploid cancers but was not related to survival. There was no benefit of adjuvant therapy in stage II nor in any of the stage II subgroups defined by mutational status. In stage III, adjuvant therapy with 5FU plus levamisole improved 7-year survival in patients with wild-type Ki-ras (76 versus 44%; HR, 0.4; 95% CI, 0.2-0.8) and in those without p53 overexpression (64 versus 26%; HR, 0.3; 95% CI, 0.1-0.7). Adjuvant therapy did not benefit those with Ki-ras mutations or p53 overexpression. The effects of adjuvant therapy did not differ according to ploidy status or proliferative rate. Ki-ras mutation is a significant risk factor for death in stage II, and the absence of p53 expression is a significant risk factor for death in stage III colon cancer after adjustment for treatment and clinical covariates. Exploratory analyses suggest that patients with stage III colon cancer with wild-type Ki-ras or no p53 expression benefit from adjuvant 5FU plus levamisole, whereas those with Ki-ras mutations or p53 overexpression do not. An independent study will be required to determine whether response to adjuvant therapy in colon cancer depends on mutational status.

[An analysis of complications after implantation of saline-filled silicone prosthesis for augmentation mammaplasty in 294 cases]

Complications after implantation of saline-filled silicone prosthesis for augmentation mammaplasty were analyzed in 294 patients after being followed for 3-5 years. The complications included hematoma, infection, capsular contraction, rupture of the implant, exposure of the implant, psychataxia and poor contour etc. Conditions in which these complications occurred, causes, clinical malifestations, prevention and treatment are discussed.

Cryopreservation of interior spruce (Picea glauca engelmanni complex) embryogenic cultures

Embryogenic cultures of interior spruce derived from 12 full-sib families were subjected to cryopreservation, with a 97 % success rate for 357 genotypes. Analyses suggested that cryotolerance was not related to family ranking (height increment), embryogenic potential or culture dispersability in suspension, and long-term storage in or above liquid nitrogen did not affect regenerative potential. By contrast, differences in cryotolerance among cell lines appeared to be prevalent in certain families. Analysis with a DNA fingerprinting probe used for clonal identification demonstrated no evidence of somaclonal variation as a result of cryopreservation. The results of this work indicate the applicability of cryopreservation as a long-term storage strategy for spruce embryogenic cultures from a wide genetic background.