Porous biochar derived from walnut shell as an efficient adsorbent for tetracycline removal

Achieving "Pesticide-Pest Mutual Management" through pest-derived biochar

This study proposes a novel "pesticide-pest mutual management" strategy, transforming the traditional unidirectional impact of pesticides on pests into a sustainable and interactive process. Using the Asian longhorned beetle (Anoplophora glabripennis, ALB) as a precursor, a series of nitrogen-rich biochars (ALB-BC) was synthesized to remove and detect insecticides used in ALB control from water. Among them, acid-modified ALB-BC (HBC 400) exhibited an exceptional adsorption capacity for thiacloprid, reaching 1591.06 mg g-1. Mechanistic studies revealed that Lewis acid-base interactions serve as the primary adsorption mechanism, underpinning ALB-BC's high affinity for thiacloprid. Additional mechanisms, including hydrogen bonding, π-π interactions, and pore filling, further enhanced adsorption performance. These interactions were attributed to the high concentrations of carbonyl and hydroxyl groups, as well as nitrogen species (e.g., pyridinic-N, pyrrolic-N) in ALB-BC, derived from the abundant peptide bonds and polysaccharide structures in ALB. Furthermore, ALB-BC effectively extracted and detected poorly water-soluble insecticides (e.g., cyhalothrin, cypermethrin, and fenitrothion) used in ALB control, alongside thiacloprid, achieving recoveries of 84 %-96 % and detection limits of 0.04-0.09 μg L-1. This study highlights the potential of utilizing forestry pest resources for sustainable applications and demonstrates promising prospects in environmental monitoring and pollution mitigation.

Ultra-effective removal of methylene blue dye and lead heavy metal from aqueous solution using novel Co and Fe co-doped magnetic activated carbon nanohybrid material from Nigella sativa (Nigella sativa L.) industrial processing wastes

In this study, a novel magnetic carbonaceous nanohybrid material (CoF@NAC) was synthesized by microwave-assisted simple chemical co-precipitation method in the basic medium using iron and cobalt nitrate salts in the presence of Nigella sativa (Nigella sativa L.) industrial processing waste-based activated carbon (NAC) and then characterized by SEM, EDX, Mapping, BET, XRD, VSM, FTIR, Boehm titration, and pHZPC techniques. Its BET surface area, total pore volume, mesoporosity, average pore diameter, and saturation magnetization values were 729 m2/g, 0.426 cm3/g, 61.5%, 2.4 nm, and 23.3 emu/g, respectively. To test its adsorptive performance, methylene blue (MB) dye and lead (Pb(II)) heavy metal water pollutants were selected as model adsorbates. Optimum adsorption conditions were determined according to the maximum effects of key experimental parameters. The kinetic and isotherm findings of each adsorption system fit best the pseudo-second-order kinetic and Langmuir isotherm models, respectively. The maximum removed MB and Pb(II) quantities of MB and Pb(II) were 667 and 455 mg/g, respectively, at their natural pH levels (pH 6 for MB and pH 5 for Pb(II)) in water. Thermodynamic parameters calculated showed that their processes were spontaneous, endothermic for MB, and exothermic for Pb(II). Moreover, it showed high recyclability stability over four cycles for the studied adsorbates.

Walnut shell-based biochar-assisted Fe sites anchored carbon-rich g-C3N4: Boosting photodegradation of 2-Mercaptobenzothiazole though synergistic enhancement of Fe sites and C substitution

To expand the utilization of discarded walnut shells and enhance the photocatalytic activity of graphitic carbon nitride(g-C3N4), the carbon-rich graphitic carbon nitride anchored with Fe sites (FeW-CN) was synthesized via a walnut shell-based biochar-assisted strategy. Unlike the direct thermal copolymerization of melamine for g-C3N4, the iron-loaded walnut shell-based biochar (FeW) was first synthesized, followed by thermal copolymerization of melamine with FeW to form FeW-CN. The C substitution on the triazine ring enhanced the light absorption and electron migration for FeW-CN. And the Fe sites interacting with N-(C)3 further improved the migration and the utilization rate of photogenerated carriers. During the degradation of 2-Mercaptobenzothiazole, FeW-CN showed excellent photocatalytic performance and stability compared with g-C3N4. Moreover, FeW-CN maintained excellent photocatalytic performance in river water. Combination of electron paramagnetic resonance with active species quenching experiments, the synergistic mechanism of singlet oxygen, holes, and superoxide radicals was confirmed in the FeW-CN system. Compared to g-C3N4, the Fe sites and C substitution enhanced the production of singlet oxygen.

Microporous carbon derived from waste plastics for efficient adsorption of tetracycline: Adsorption mechanism and application potentials

In recent years, the accumulation of waste plastics and emergence plastic-derived pollutants such as microplastics have driven significantly the development and updating of waste plastic utilization technology. This study prepared the porous carbon (PC-1-KOH) material directly from polyethylene terephthalate (PET) in waste plastic bottles using KOH activation and molten salt strategy for efficient removal of antibiotic tetracycline (TC). The maximum removal efficiency of TC was 100.0% with a PC-1-KOH weight of 20 mg. In addition, the TC removal efficiency stayed over 80.0% within the rage of pH of 3-9 and different water bodies. The adsorption process was described by the Pseudo-second-order kinetic model and the Langmuir isotherm, suggesting that the adsorption of TC was predominantly chemical in nature and occurred on a homogeneous surface. The pores filling, hydrogen bonding, π-π stacking interactions and electrostatic interaction are the main mechanisms of TC adsorption. This work demonstrates a sustainable approach to converting plastic waste derived materials into functional materials for effective pollution removal and environmental remediation.

Insight into enhanced tetracycline photodegradation by hematite/biochar composites: Roles of charge transfer, biochar-derived dissolved organic matter and persistent free radicals

The combination of hematite and biochar significantly accelerated tetracycline (TC) removal under visible light irradiation. The kinit of TC removal with Hem/BC-5 reached 0.103 min-1, 3.8 and 6.1 times faster than those with hematite and biochar, attributed to boosting free radicals. The enhanced light absorption and charge transfer helped generate more H2O2 and •OH through 2e- oxygen reduction and direct valence band (VB) oxidation. Persistent free radicals (PFRs) on biochar helped generate H2O2. Biochar as electron shutter facilitated Fe3+/Fe2+ redox cycling and triggered more efficient photo-Fenton reaction. Biochar-derived dissolved organic matter (DOM) helped generate 3DOM*, a reactive intermediate to produce H2O2, •OH, and 1O2. Hem/BC composites have excellent photoactivity for the degradation of TC in different water matrixes under visible light irradiation. The degradation pathway was proposed based on theoretical calculation and detected degradation intermediates. These findings contribute to the development of biochar-based catalysts for organic pollutants removal.

Bimetallic Zinc-Iron-Modified Sugarcane Bagasse Biochar for Simultaneous Adsorption of Arsenic and Oxytetracycline from Wastewater

Arsenic (As), a highly toxic and carcinogenic heavy metal, poses significant risks to soil and water quality, while oxytetracycline (OTC), a widely used antibiotic, contributes to environmental pollution due to excessive human usage. Addressing the coexistence of multiple pollutants in the environment, this study investigates the simultaneous adsorption of As(III) and OTC using a novel bimetallic zinc-iron-modified biochar (1Zn-1Fe-1SBC). The developed adsorbent demonstrates enhanced recovery, improved adsorption efficiency, and cost-effective operation. Characterization results revealed a high carbon-to-hydrogen ratio (C/H) and a specific surface area of 1137 m2 g-1 for 1Zn-1Fe-1SBC. Isotherm modeling indicated maximum adsorption capacities of 34.7 mg g-1 for As(III) and 172.4 mg g-1 for OTC. Thermodynamic analysis confirmed that the adsorption processes for both pollutants were spontaneous (ΔG < 0), endothermic (ΔH > 0), and driven by chemical adsorption (ΔH > 80 kJ mol-1), with increased system disorder (ΔS > 0). The adsorption mechanisms involved multiple interactions, including pore filling, hydrogen bonding, electrostatic attraction, complexation, and π-π interactions. These findings underscore the potential of 1Zn-1Fe-1SBC as a promising adsorbent for the remediation of wastewater containing coexisting pollutants.

What is the potential of walnut shell-derived carbon in battery applications?

The environmental implications of utilizing walnut shells (WSs) as a material for energy storage are complex, balanced between advancing technologies and improving efficiency. This review aims to address, for the first time, environmental concerns and health effects associated with this material by conducting an in-depth analysis of carbon materials derived from waste management systems. Beginning with a reevaluation of the structural characteristics, cellular morphology, and physicochemical properties of WSs, this study explores their potential for the efficient synthesis of carbon. By examining various methods for the production of WS-derived materials such as hard carbon, we demonstrate the multifaceted nature of WS biomass as a resource. Subsequently, we shift our focus to ion storage mechanisms in the carbon source (C-S), including storage sensitivity, ion intercalation in micropores, and layer intercalation. An electrochemical analysis of the carbon source reveals its potential applications in energy storage systems. Furthermore, life cycle analysis was employed to assess the environmental impact and economic viability of WS utilization. The findings of the analysis suggest that one of the most valuable attributes of WSs is their potential for creating more environmentally sustainable materials, encouraging researchers to promote the use of green components in sodium batteries. This review underscores, for the first time, the significance of WSs in the field of carbon energy storage and their potential to enhance future prospects. The substantial opportunities in this area warrant further research and development, highlighting the relevance of WS-derived materials in advancing sustainable energy storage solutions.

Research on the Adsorption Mechanism and Performance of Cotton Stalk-Based Biochar

In this research, we produced two types of biochar (BC) using cotton stalks as raw material and KOH as an activator, and compared their performance and adsorption mechanisms in the removal of tetracycline (TC) and methylene blue (MB) from wastewater. The results showed that the biochar generated using both procedures formed pores that connected to the interior of the biochar and had extensive microporous and mesoporous structures. The molten salt approach produces biochar with a higher specific surface area, larger pore size, and higher pore volume than the impregnation method, with a maximum specific surface area of 3095 m2/g. KBCM-900 (the BC produced using the molten salt method at 900 °C) had a better adsorption effect on TC, with a clearance rate of more than 95% in 180 min and a maximum adsorption amount of 912.212 mg/g. The adsorption rates of the two BCs for MB did not differ significantly at low concentrations, but as the concentration increased, KBCI-900 (the BC generated by the impregnation method at 900 °C) exhibited better adsorption, with a maximum adsorption of 723.726 mg/g. The pseudo-second-order kinetic model and the Langmuir isotherm model may accurately describe the TC and MB adsorption processes of KBCI-900 and KBCM-900. The KBCI/KBCM-900 adsorption process combines physical and chemical adsorption, with the primary mechanisms being pore filling, π-π interactions, hydrogen bonding, and electrostatic interactions. As a result, biochar generated using the molten salt method is suitable for the removal of large-molecule pollutants such as TC, whereas biochar prepared using the impregnation method is suitable for the removal of small-molecule dyes such as MB.

Magnesium Bicarbonate-Walnut Shell Dual-Template Synthesis of Multifunctional Layered Porous Carbon for Enhanced Adsorption of Aqueous Chlorinated Organic Compounds

Chloride ions readily react with organic matter and other ions, resulting in the formation of disinfection by-products (DBPs) that exhibit heightened levels of toxicity, carcinogenicity, and mutagenicity. This study creatively employed waste walnut shells as self-templates and low-cost magnesium bicarbonate as a rigid template to successfully synthesize multifunctional porous carbon derived from walnut shells. Employing a series of characterization techniques, it was ascertained that the porous carbon material (WSC/Mg) synthesized via the dual-template method exhibited a distinct layered microscopic surface structure, with a predominance of C and O elements on the surface. The material displayed a high degree of graphitization, significant specific surface area, and abundant oxygen-containing surface functional groups. The incorporation of magnesium bicarbonate as a hard template improved the structure of the walnut shell porous carbon, resulting in a significant enhancement in mass transfer efficiency for the target product on the adsorbent and a substantial improvement in removal efficiency. In comparison with walnut shell-derived carbon using only self-templating, WSC/Mg exhibited a 17.26-fold increase in adsorption capacity for 2,4-dichlorophenol. Furthermore, even after four adsorption-desorption cycles, WSC/Mg-12 maintained an adsorption efficiency above 90%. It is remarkable that WSC/Mg-12 demonstrated exceptional resistance to interference from natural organic matter and pH variations. Moreover, the adsorbed saturated WSC/Mg-12 effectively treated real coke wastewater, resulting in an 80% color removal rate, 20% COD removal rate, and 15% ammonia nitrogen removal rate. In conclusion, this study presents an innovative approach for cost-effective and versatile porous carbon materials with extensive applications in water environment purification and biomass utilization.

Mechanism of adsorption and targeted degradation of antimicrobial micropollutant sulfamethoxazole in aquatic environments

FHWSB as an integrated absorptive catalyst, based on Walnut shell biochar (WSB) via hydrochloric acid modification and ferrous chloride impregnation, was prepared, reacted with H2O2 to generate active free radicals •OH and •O2-, which oxidized and degraded about 80% of micro-pollutant sulfamethoxazole (SMX) from water, effectively resolving micro-pollutants' removal being inefficient because of high toxicity, persistence, and bioaccumulation in existed methods. It was clarified the specific degradation pathways and mechanisms of SMX by FHWSB synergistic H2O2 via characterization and analysis assisted DFT calculations. Furthermore, it was found that the toxicity of a series of intermediates produced by SMX degraded continued to decline, consistent with its direction of degradation via toxicological analysis. The work provides a simple and feasible strategy for the effective removal of antibiotic micro-pollutants in aquatic environments.

Enhancing solid-phase extraction of tetracyclines with a hybrid biochar sorbent: A comparative study of chlorella and bamboo biochars

Biochar, a sustainable sorbent derived from pyrolyzed biomass, has garnered attention for its efficacy in solid-phase extraction (SPE) of antibiotics, with a particular focus on tetracyclines (TCs). Despite its recognized potential, the intricate separation mechanisms operative in biochar-based SPE systems have not been fully deciphered. This investigation contrasts chlorella biochar against commercial bamboo biochar, harnessing an array of analytical methodologies-microstructure characterization, adsorption thermodynamics, competitive adsorption kinetics, H+ back titration, and selectivity adsorption studies-complemented by a Box-Behnken design for the optimization of chlorella/bamboo-SPE and subsequent application in the analysis of animal-derived foodstuffs. The study unveils that a hybrid sorbent, integrating nitrogen-doped microporous chlorella biochar with mesoporous bamboo biochar in a 95/5 mass ratio, markedly diminishes irreversible adsorption while enhancing selectivity, surpassing the performance of single biochar SPE systems. The elucidated separation mechanisms implicate a partition model, propelled by oxygen-rich functional groups on chlorella biochar and the rapid adsorption kinetics of bamboo biochar, all orchestrated by electrostatic interactions within the mixed biochar framework. Moreover, the synergy of mixed biochar-SPE with high-performance liquid chromatography (HPLC) demonstrates exceptional proficiency in detecting TCs in animal viscera, evidenced by recovery rates spanning 80.80 % to 106.98 % and RSDs ranging from 0.24 % to 14.69 %. In essence, this research not only sheds light on the multifaceted factors influencing SPE efficiency but also propels the use of biochar towards new horizons in environmental monitoring and food safety assurance.

Enhanced degradation of reactive black 5 via persulfate activation by natural bornite: influencing parameters, mechanism and degradation pathway

Reactive black 5 (RBk5) is a refractory azo dye that constitutes a serious threat to the environment and humans. Herein, natural bornite (Nbo) was utilized to activate persulfate (PDS) for the RBk5 removal. The particle size of the Nbo catalyst was optimized and the RBk5 degradation rate constant that responded positively to the particle size of the Nbo catalyst was exhibited. Then, the operational factors affecting RBk5 removal were comprehensively investigated. With the addition of 1.5 g L-1 Nbo and 1.5 mM PDS, 99.05% of the RBk5 (20 mg L-1) was removed in 150 min compared with 0.46% removal with PDS only, which was caused by the additional reactive oxygen species (ROS) produced by the synergistic action of Fe-Cu bimetallic metal and reductive sulfur species. The Nbo catalyst presented high stability and reusability toward RBk5 removal. Identification of reactive oxygen species revealed that SO 4 ⋅ - , ·OH, O 2 ⋅ - and 1O2 collectively participated in RBk5 removal. Additionally, a possible degradation pathway for RBk5 was proposed, including cleavage of the azo, C-S and S-O bonds, hydroxylation, hydrolyzation, direct oxidation and other pathways. This work developed a highly effective and low-cost natural mineral-based bimetallic sulfide material for PDS activation for the degradation of contaminants and environmental remediation.

Preparation of Activated Biocarbons from Cones and their Potential Application for Adsorption of Antibiotics (Tetracycline)

The pine cones (PC), spruce cones (SC) and fir cones (FC) were used for biocarbons preparation. Chemical activation with sodium hydroxide was applied to prepare activated biocarbons. All the materials under investigation were characterized by the N2 adsorption, scanning electron microscopy (SEM), elemental analysis (CHNS), infrared spectroscopy (ATR FT-IR), and the Boehm's titration method. Moreover, pHpzc (the point of zero charge) was determined. It was shown that cones are a good, cheap precursor from which biocarbons with a developed porous structure, characterized by good adsorption properties, can be obtained. All the obtained adsorbents are characterized mainly by a microporous structure. Moreover, they contain both acidic and basic surface functional groups (acidic ones prevail over basic ones). The tested activated biocarbons have large specific surface area values ranging from 578 to 1182 m2 g-1. The efficacy of selected materials in the adsorption of an essential contaminant of increasing concern, tetracycline (TC), was investigated. The experimental data were described using the Langmuir and Freundlich adsorption isotherm models. The maximum adsorption capacity of the tested biocarbons ranges from 200 to 392 mg g-1. Thermodynamic studies proved that adsorption is a spontaneous and endothermic process. In summary, economical and environmentally friendly adsorbents were obtained.

Fabrication of nano-hammer shaped CuO@HApNWs for catalytic degradation of tetracycline

With widespread and excessive use of antibiotics in medicine, poultry farming, and aquaculture, antibiotic residues have become a significant threat to both eco-environment and human health. In this paper, using hydroxyapatite nanowires (HApNWs) as an ecologically compatible carrier, a novel nano-hammer shaped conjunction with HApNW conjugating CuO microspheres (CuO@HApNWs) was successfully synthesized by in-situ agglomeration method. The catalytic degradation performance of the nano-hammer shaped CuO@HApNWs with Fenton-like activation was investigated by using tetracycline (TC) as a representative antibiotic pollutant. Remarkably, it exhibited excellent catalytic activity, which the removal rate of TC got to 92.0% within 40 min, and the pseudo-second-order reaction kinetic constant was 18.33 × 10-3 L mg-1·min-1, which was 26 times and 5 times than that of HApNWs and CuO, respectively. Furthermore, after recycling 6 times, the degradation efficiency of TC still remained above 85 %. Based on radical scavenger tests and electron paramagnetic resonance (EPR) spectroscopy, it demonstrated that the excellent activity of CuO@HApNWs was mainly attributed to the fact that Fenton-like activation promotes the circulation of Cu2+ and Cu+, the generated main active oxygen species (•OH and O2-•) achieve efficient degradation of TC. In summary, the nano-hammer shaped CuO@HApNWs could be in-situ synthesed, and used as an eco-friendly Fenton-like catalyst for effectively catalytic degradation of organic pollutants, which has great potential for wastewater treatment.

Removal of ofloxacin using a porous carbon microfiltration membrane based on in-situ generated •OH

This study investigated the removal performance of ofloxacin (OFL) by a novel electro-Fenton enhanced microfiltration membrane. The membranes used in this study consisted of metal-organic framework derived porous carbon, carbon nanotubes and Fe2+, which were able to produce hydroxyl radicals (•OH) in-situ via reducing O2 to hydrogen peroxide. Herein, membrane filtration with bias not only concentrated the pollutants to the level that could be efficiently treated by electro-Fenton but also confined/retained the toxic intermediates within the membrane to ensure a prolonged contact time with the oxidants. After validated by experiments, the applied bias of -1.0 V, pH of 3 and electrolyte concentration of 0.1 M were the relatively optimum conditions for OFL degradation. Under these conditions, the average OFL removal rate could be reach 75% with merely 5% membrane flux loss after 4 cycles operation by filtrating 1 mg/L OFL. Via decarboxylation reaction, piperazinyl ring opening, dealkylation and ipso substitution reaction, etc., OFL could be gradually and efficiently degraded to intermediate products and even to CO2 by •OH. Moreover, the oxidation reaction was preferred to following first-order reaction kinetics. This research verified a possibility for antibiotic removal by electro-enhanced microfiltration membrane.

Efficient Adsorbent Derived from Phytolith-Rich Ore for Removal of Tetracycline in Wastewater

In recent decades, the tetracycline (TC) concentration in aquatic ecosystems has gradually increased, leading to water pollution problems. Various mineral adsorbents for the removal of tetracyclines have garnered considerable attention. However, efficient adsorbents suitable for use in a wide pH range environment have rarely been reported. Herein, a phytolith-rich adsorbent (PRADS) was prepared by a simple one-step alkali-activated pyrolysis treatment using phytolith as a raw material for effectively removing TC. PRADS, benefiting from its porous structure, which consists of acid- and alkali-resistant, fast-adsorbing macroporous silica and mesoporous carbon, is highly desirable for efficient TC removal from wastewater. The results indicate that PRADS exhibited excellent adsorption performance and stability for TC over a wide pH range of 2.0-12.0 under the coexistence of competing ions, which could be attributed to the fact that PRADS has a porous structure and contains abundant oxygen-containing functional groups and a large number of bonding sites. The adsorption mechanisms of PRADS for TC were mainly attributed to pore filling, hydrogen bonding, π-π electron-donor-acceptor, and electrostatic interactions. This work could offer a novel preparation strategy for the effective adsorption of pollutants by new functionalized phytolith adsorbents.

Enhanced Adsorptive Removal of Tetracycline by Phosphomolybdic Acid-Modified Low-Temperature Sludge Biochar

Increasing the adsorption capacity and reducing the energy consumption of sludge biochar during preparation is important. In this study, a new modification method was developed to prepare phosphomolybdic acid-modified sludge biochar through the low-temperature pyrolysis of sewage sludge using phosphomolybdic acid as a modifier. Tetracycline was used to assess the adsorption performance of sludge biochar, and phosphomolybdic acid-modified sludge biochar was prepared at different temperatures. The results showed that the adsorption capacity of sludge biochar improved from 84.49 to 120.86 mg/g through modification with phosphomolybdic acid at 200 °C. The maximum adsorption capacities of phosphomolybdic acid-modified sludge biochar (200 °C pyrolysis temperature) at 298, 308, and 318 K were 283.87, 421.39, and 545.48 mg/g, respectively. Both liquid film and intraparticle diffusion were the main rate-limiting steps of tetracycline adsorption by phosphomolybdic acid-modified sludge biochar. Furthermore, the adsorption of tetracycline by phosphomolybdic acid-modified sludge biochar was mainly attributed to π-π interactions, electrostatic interactions, hydrogen bonding, and pore filling.

Highly porous BiOBr@NU-1000 Z-scheme heterojunctions for synergistic efficient adsorption and photocatalytic degradation of tetracycline

Designing an effective photoactive heterojunction having dual benefits towards photoenergy conversion and pollutant adsorption is regarded as an affordable, green method for eliminating tetracycline (TC) from wastewater. In this regard, a series of BiOBr@NU-1000 (BNU-X, X = 1, 2 and 3) heterojunction photocatalysts are constructed. BNU-X preserves the original skeleton structure of the parent NU-1000, and its high porosity and specific surface area enable superior TC adsorption. At the same time, BNU-X is an effective Z-scheme photocatalyst that improves light trapping, promotes photoelectron-hole separation, and shows excellent photocatalytic degradation efficiency towards TC with the value of the photodegradation kinetic rate constant k being 2.2 and 24.8 times those of NU-1000 and BiOBr, respectively. The significant increase in the photocatalytic activity is ascribed to the construction of an efficient Z-scheme photocatalyst, which promotes the formation of superoxide radicals (˙O2-) and singlet oxygen (1O2) as the main oxidative species in the oxidation system. This research has the advantage of possibilities for the development of porous Z-scheme photocatalysts based on photoactive MOF materials and inorganic semiconductors for the self-purification and photodegradation of organic contaminants.

Synergistic mechanisms for the superior sorptive removal of aquatic pollutants via functionalized biochar-clay composite

This study investigated the successful synthesis of functionalized algal biochar-clay composite (FBKC). Subsequently, the sorption performance of FBKC towards norfloxacin (NFX) antibiotic and crystal violet dye (CVD) from water was extensively assessed in both batch and continuous flow systems. A series of characterization techniques were carried out for FBKC and the utilized precursors, indicating that the surface area of FBKC was increased thirty-fold with a well-developed pore structure compared to the original precursors. FBKC demonstrated a maximum sorption capacity of 192.80 and 281.24 mg/g for NFX and CVD, respectively. The suited fitting of the experimental data to Freundlich and Clark models suggested multi-layer sorption of NFX/CVD molecules. The mechanistic studies of NFX/CVD sorption onto FBKC unveiled multiple mechanisms, including π-π interaction, hydrogen bonding, electrostatic attraction, and surface/pore filling effect. The estimated cost of 5.72 €/kg and superior sorption capacity makes FBKC an efficient low-cost sorbent for emergent water pollutants.

Construction of cubic CaTiO3 perovskite modified by highly-dispersed cobalt for efficient catalytic degradation of psychoactive pharmaceuticals

Sulfate radical mediated advanced oxidation processes (SR-AOPs) have emerged as a promising alternative for emerging contaminants degradation. However, high activity and great stability are commonly difficult to juggle, and the structure-activity correlations are still ambiguous. This study constructed the cubic CaTiO3 perovskite modified by highly-dispersed cobalt for peroxymonosulfate (PMS) activation to improve the specific lattice plane exposure and reduce the metal leaching simultaneously. 98% of amitriptyline (AMT) degradation was achieved within 60 min under the condition of 200 mg/L Co0.1-CTO and 100 mg/L PMS. The results indicated that surface Co2+/Co3+ redox couple and lattice oxygen were responsible for PMS activation, and the evolution of ·OH, SO4·- and 1O2 were revealed. According to density functional theory (DFT) calculations, the highly-dispersed Co on cubic surface effectively captured PMS and promoted electron transfer for the generation of ·OH and SO4·-, while more oxygen atoms exposed on Co0.1-CTO(200) surface facilitated the generation of 1O2. Briefly, this study provides a novel strategy of catalyst synthesis in PMS activation for water treatment.

Synthesis of Porous MgAl-LDH on a Micelle Template and Its Application for Efficient Treatment of Oilfield Wastewater

In this paper, a series of porous hierarchical Mg/Al layered double hydroxides (named as LDH, TTAC-MgAl-LDH, CTAC-MgAl-LDH, and OTAC-MgAl-LDH) was synthesized by a simple green hydrothermal method using wormlike micelles formed by salicylic acid and surfactants with different carbon chain lengths (0, 14, 16, and 18) as soft templates. BET, XRD, FTIR, TG, and SEM characterizations were carried out in order to investigate the structure and properties of the prepared materials. The results showed that the porous hierarchical CTAC-MgAl-LDH had a large specific surface area and multiple pore size distributions which could effectively increase the reaction area and allow better absorption capability. Benefiting from the unique architecture, CTAC-MgAl-LDH exhibited a large adsorption capacity for sulfonated lignite (231.70 mg/g) at 25 °C and a pH of 7, which outperformed the traditional LDH (86.05 mg/g), TTAC-MgAl-LDH (108.15 mg/g), and OTAC-MgAl-LDH (110.51 mg/g). The adsorption process of sulfonated lignite followed the pseudo-second-order kinetics model and conformed the Freundlich isotherm model with spontaneous heat absorption, which revealed that electrostatic adsorption and ion exchange were the main mechanisms of action for the adsorption. In addition, CTAC-MgAl-LDH showed a satisfactory long-time stability and its adsorption capacities were still as high as 198.64 mg/g after two adsorption cycles.

Highly efficient nanocomposite of Y2O3@biochar for oxytetracycline removal from solution: Adsorption characteristics and mechanisms

Nano Y₂O₃-modified biochar composites (Y₂O₃@BC600) were fabricated successfully and exhibited great adsorption toward oxytetracycline (OTC). The Langmuir adsorption capacity of Y₂O₃@BC600-1:4 for OTC reached 223.46 mg/g, 10.52 times greater than that of BC600. The higher dispersion of Y₂O₃ nanoparticles, increased surface area of 175.65 m²/g and expanded porosity of 0.27 cm³/g accounted for higher OTC adsorption by Y₂O₃@BC600-1:4. Y₂O₃@BC600-1:4 could resist the interference of co-existing cations (Na⁺, K⁺, Mg²⁺, Ca²⁺) and anions (Cl^-, NO₃^-, SO₄^2-) on OTC removal. Y₂O₃ coating changed surface charge property of BC600, favoring the contribution of electrostatic interaction. Synchrotron radiation-based Fourier transform infrared spectroscopy detected obvious peak shift and intensity change of surface -OH when OTC adsorption occurred. Accordingly, stronger H-bonding (charge-assisted hydrogen bond, OTC-H₂N⁺···HO-Y₂O₃@BC600-1:4) was proposed for OTC adsorption. Y₂O₃@BC600 exhibited renewability and stability in the adsorptive removal of OTC. Therefore, Y₂O₃@BC600 may be a novel and suitable adsorbent for antibiotic removal.