Waste-to-Resource Strategy to Fabricate Functionalized MOFs Composite Material Based on Durian Shell Biomass Carbon Fiber and Fe3O4 for Highly Efficient and Recyclable Dye Adsorption

Fabrication of novel multifunctional copper-functionalized hemp fibers to remove anionic dye and non-steroidal anti-inflammatory drugs from wastewaters

This research aims to design a novel selective and multifunctional adsorbent based on Al/Cu modified hemp fibres as a novel and multifunctional adsorbent for removing different classes of pollutants. The adsorbent, which was widely characterized, was shown to be more effective in removing anionic dyes compared to cationic ones. Among the tested dyes, methyl orange (MO) was selected to understand how different parameters, such as temperature (20-80 °C), contact time, pH (2-12), initial dye concentration (50-300 ppm), salinity and adsorbent dosage (1-10 g/L) affect the removal capacity. The Langmuir model greatly describes the adsorption data with a qm = 338.98 mg/g. Thermodynamic calculation proved that the adsorption process is spontaneous (negative ΔG) and endothermic (positive enthalpy) while the adsorption process is governed by either film or pore diffusion. The Design of Experiment algorithm was adopted to predict the recovery of MO through a response surface model by varying simultaneously the pH, temperature and initial dye concentration, in accordance with the experimental data. It was demonstrated the multifunctional properties of the produced adsorbent since it showed a great selectivity in removing two anti-inflammatory drugs (91% for piroxicam and 34% for diclofenc sodium salt). Finally, the selective removal of different anionic dyes in a mixed solution was proved, following the order methyl orange>congo red>acid yellow 17. The reported approach presents a sustainable, low-cost option for the preparation of novel and effective adsorbents with interesting properties to achieve remarkable adsorption of anionic dyes and anti-inflammatory drugs with a great reusability.

Magnetic biochar as a revolutionizing approach for diverse dye pollutants elimination: A comprehensive review

The term "biomass" encompasses all substances found in the natural world that were once alive or derived from living organisms or their byproducts. These substances consist of organic molecules containing hydrogen, typically oxygen, frequently nitrogen, and small amounts of heavy, alkaline earth and alkali metals. Magnetic biochar refers to a type of material derived from biomass that has been magnetized typically by adding magnetic components such as magnetic iron oxides to display magnetic properties. These materials are extensively applicable in widespread areas like environmental remediation and catalysis. The magnetic properties of these compounds made them ideal for practical applications through their easy separation from a reaction mixture or environmental sample by applying a magnetic field. With the evolving global strategy focused on protecting the planet and moving towards a circular, cost-effective economy, natural compounds, and biomass have become particularly important in the field of biochemistry. The current research explores a comparative analysis of the versatility and potential of biomass for eliminating dyes as a sustainable, economical, easy, compatible, and biodegradable method. The elimination study focused on the removal of various dyes as pollutants. Various operational parameters which influenced the dye removal process were also discussed. Furthermore, the research explained, in detail, adsorption kinetic models, types of isotherms, and desorption properties of magnetic biochar adsorbents. This comprehensive review offers an advanced framework for the effective use of magnetic biochar, removing dyes from textile wastewater.

A comprehensive review on the production of durian fruit waste-derived bioadsorbents for water treatment

Global water pollution by various pollutants is becoming an urgent problem. The conversion of durian fruit waste into adsorbents can help to mitigate this issue. Transforming durian waste into adsorbents can reduce pollution risk from waste discharged directly into the environment, while also effectively eliminating existing contaminants. Here, this work explores the potential of durian fruit waste and supplies insights into the synthesis and application of durian fruit waste-derived adsorbents such as biosorbents, modified-biosorbents, biochars, activated carbons, and composites. Several factors affecting the adsorption process of pollutants and the mechanism how pollutants can be adsorbed onto durian fruit waste-derived adsorbents are elucidated. This review also analyzes some aspects of limitations and prospects of biosorbents derived from durian fruit waste. It is anticipated that the promising properties and applications of durian fruit waste-derived adsorbents open up a new field for water waste treatment.

Synthesis of MnFe2O4/activated carbon derived from durian shell waste for removal of indole in water: Optimization, modelling, and mechanism

While durian shell is often discharged into landfills, this waste can be a potential and zero-cost raw material to synthesize carbon-based adsorbents with purposes of saving costs and minimizing environmental contamination. Indole (IDO) is one of serious organic pollutants that influence aquatic species and human health; hence, the necessity for IDO removal is worth considering. Here, we synthesized a magnetic composite, denoted as MFOAC, based on activated carbon (AC) derived from durian shell waste incorporated with MnFe2O4 (MFO) to adsorb IDO in water. MFOAC showed a microporous structure, along with a high surface area and pore volume, at 518.9 m2/g, and 0.106 cm3/g, respectively. Optimization of factors affecting the IDO removal of MFOAC were implemented by Box-Behnken design and response surface methodology. Adsorption kinetics and isotherms suggested a suitable model for MFOAC to remove IDO. MFOAC was recyclable with 3 cycles. Main interactions involving in the IDO adsorption mechanism onto MFOAC were clarified, including pore filling, n-π interaction, π-π interaction, Yoshida H-bonding, H-bonding.

Highly Efficient Separation of Ethanol Amines and Cyanides via Ionic Magnetic Mesoporous Nanomaterials

Simple and efficient sample pretreatment methods are important for analysis and detection of chemical warfare agents (CWAs) in environmental and biological samples. Despite many commercial materials or reagents that have been already applied in sample preparation, such as SPE columns, few materials with specificity have been utilized for purification or enrichment. In this study, ionic magnetic mesoporous nanomaterials such as poly(4-VB)@M-MSNs (magnetic mesoporous silicon nanoparticles modified by 4-vinyl benzene sulfonic acid) and Co2+@M-MSNs (magnetic mesoporous silicon nanoparticles modified by cobalt ions) with high absorptivity for ethanol amines (EAs, nitrogen mustard degradation products) and cyanide were successfully synthesized. The special nanomaterials were obtained by modification of magnetic mesoporous particles prepared based on co-precipitation using -SO3H and Co2+. The materials were fully characterized in terms of their composition and structure. The results indicated that poly(4-VB)@M-MSNs or Co2+@M-MSNs had an unambiguous core-shell structure with a BET of 341.7 m2·g-1 and a saturation magnetization intensity of 60.66 emu·g-1 which indicated the good thermal stability. Poly(4-VB)@M-MSNs showed selective adsorption for EAs while the Co2+@M-MSNs were for cyanide, respectively. The adsorption capacity quickly reached the adsorption equilibrium within the 90 s. The saturated adsorption amounts were MDEA = 35.83 mg·g-1, EDEA = 35.00 mg·g-1, TEA = 17.90 mg·g-1 and CN-= 31.48 mg·g-1, respectively. Meanwhile, the adsorption capacities could be maintained at 50-70% after three adsorption-desorption cycles. The adsorption isotherms were confirmed as the Langmuir equation and the Freundlich equation, respectively, and the adsorption mechanism was determined by DFT calculation. The adsorbents were applied for enrichment of targets in actual samples, which showed great potential for the verification of chemical weapons and the destruction of toxic chemicals.

Birnessite-Type MnO2 Modified Sustainable Biomass Fiber toward Adsorption Removal Heavy Metal Ion from Actual River Aquatic Environment

In this work, a novel birnessite-type MnO2 modified corn husk sustainable biomass fiber (MnO2@CHF) adsorbent was fabricated for efficient cadmium (Cd) removal from aquatic environments. MnO2@CHF was designed from KMnO4 hydrothermally treated with corn husk fibers. Various characterization revealed that MnO2@CHF possessed the hierarchical structure nanosheets, large specific surface area, and multiple oxygen-containing functional groups. Batch adsorption experimental results indicated that the highest Cd (II) removal rate could be obtained at the optimal conditions of adsorbent amount of 0.200 g/L, adsorption time of 600 min, pH 6.00, and temperature of 40.0 °C. Adsorption isotherm and kinetics results showed that Cd (II) adsorption behavior on MnO2@CHF was a monolayer adsorption process and dominated by chemisorption and intraparticle diffusion. The optimum adsorption capacity (Langmuir model) of Cd (II) on MnO2@CHF was 23.0 mg/g, which was higher than those of other reported common biomass adsorbent materials. Further investigation indicated that the adsorption of Cd (II) on MnO2@CHF involved mainly ion exchange, surface complexation, redox reaction, and electrostatic attraction. Moreover, the maximum Cd (II) removal rate on MnO2@CHF from natural river samples (Xicheng Canal) could reach 59.2% during the first cycle test. This study showed that MnO2@CHF was an ideal candidate in Cd (II) practical application treatment, providing references for resource utilization of agricultural wastes for heavy metal removal.

Rational Construction of MOF-Derived Porous ZnTiO3/TiO2 Heterostructured Photocatalysts with Remarkable Photocatalytic Performance

TiO2 has been widely used in photodegradation of pollutants, but it suffers from inferior photocatalytic performance under solar light illumination. Thus, novel porous ZnTiO3/TiO2 heterostructured photocatalysts are constructed by hydrothermal and carbonization techniques using ZIF-8 as a sacrificial template. After coating with TiO2, ZIF-8 nanocubes are selectively etched and subsequently coprecipitated with Ti ions during the hydrothermal process. Thereafter, the pores generated from carbonized ZIF-8 provide a large specific surface area and abundant active reaction sites for photocatalysis after annealing, producing stable ZnTiO3/TiO2 nanocomposites. Thus, porous ZnTiO3/TiO2 heterostructured photocatalysts exhibit excellent photocatalytic performance under solar light irradiation due to the boosted electron-hole separation/transfer. The kinetic constant of ZnTiO3/TiO2 nanocomposites (4.66 × 10-1 min-1) is almost 100 and 3.7 times higher than that of self-degradation (4.69 × 10-3 min-1) and TiO2 (1.27 × 10-1 min-1), respectively. This facile strategy provides a deep insight into synthesizing heterostructured photocatalysts with high efficiency in the field of environmental remediation.

High Rate Performance Supercapacitors Based on N, O Co-Doped Hierarchical Porous Carbon Foams Synthesized via Chemical Blowing and Dual Templates

N, O Co-Doped porous carbon materials are promising electrode materials for supercapacitors. However, it is still a challenge to prepare high capacitance performance N, O Co-Doped porous carbon materials with balanced pore structure. In this work, a simple chemical blowing method was developed to produce hierarchal porous carbon materials with Zn(NO3)2·6H2O and Fe(NO3)3·9H2O as the foaming agents and precursors of dual templates. Soybean protein isolate served as a self-doping carbon source. The amount of Fe(NO3)3·9H2O influenced the microstructure, element content and capacitance performance of the obtained porous carbon materials. The optimized sample CZnFe-5 with the addition of 5% Fe(NO3)3·9H2O displayed the best capacitance performance. The specific capacitance reached 271 F g-1 at 0.2 A g-1 and retained 133 F g-1 at 100 A g-1. The CZnFe-5//CZnFe-5 symmetric supercapacitors delivered a maximum energy density of 16.83 Wh kg-1 and good stability with capacitance retention of 86.33% after 40,000 cycles tests at 50 A g-1. The symmetric supercapacitors exhibited potential applications in lighting LED bulbs with a voltage of 3 V. This work provides a new strategy for the synthesis of hierarchical porous carbon materials for supercapacitors from low-cost biomass products.

Synthesis and applications of biomass-derived porous carbon materials in energy utilization and environmental remediation

Renewable biomass and its waste are considered among the most promising applications materials owing to the depletion of fossil fuel and concerns about environmental pollution. Notably, advanced porous carbon materials derived from carbon-rich biomass precursors exhibit controllable pore structures, large surface areas, natural microstructures, and abundant functional groups. In addition, these three-dimensional structures provide sufficient reaction sites and fascinating physicochemical properties that are conducive to heteroatom doping and functional modification. This review systematically summarizes the design methods and related mechanisms of biomass-derived porous carbon materials (BDPCMs), discusses how the synthesis conditions influence the structure and performance of the carbon material, and emphasizes the importance of its use in energy utilization and environmental remediation applications. Current BDPCMs challenges and future development strategies are finally discussed to provide systematic information for further synthesis and performance optimization, which are expected to lead to novel ideas for the future development of bio-based carbon materials.

Magnetic Luffa-Leaf-Derived Hierarchical Porous Biochar for Efficient Removal of Rhodamine B and Tetracycline Hydrochloride

Luffa leaf (LL) is an agricultural waste produced by loofah. In this work, LL was used as biomass carbon source for biochars for the first time. After carbonization, activation, and chemical co-precipitation treatments, a magnetic lignocellulose-derived hierarchical porous biochar was obtained. The specific surface area and total pore volume were 2565.4 m²/g and 1.4643 cm³/g, and the surface was rich in carbon and oxygen functional groups. The synthetic dye rhodamine B (RhB) and the antibiotic tetracycline hydrochloride (TH) were selected as organic pollutant models to explore the ability to remove organic pollutants, and the results showed good adsorption performances. The maximum adsorption capacities were 1701.7 mg/g for RhB and 1755.9 mg/g for TH, which were higher than most carbon-based adsorbents. After 10 cycles of use, the removal efficiencies were still maintained at more than 70%, showing good stability. This work not only verified the feasibility of lignocellulose LL as a carbon source to prepare biochar but also prepared a magnetic hierarchical porous adsorbent with good performances that can better treat RhB and TH, which provided a new idea and direction for the efficient removal of organic pollutants in water.

Influence of Microbial Treatment on the Preparation of Porous Biochar with Stepped-Up Performance and Its Application in Organic Pollutants Control

In this study, Irisensata Thunb grass (ITG) was used as a biomass carbon resource to prepare biochars for the first time. After microbial treatment, the obtained microbial-treated ITG (MITG) was activated by using a mixed base as an activator for preparation of biochar (MITGB). The specific surface area and total pore volume of MITGB were 3036.4 m²/g and 1.5252 cm³/g, which were higher than those of biochar prepared without microbial treatment (ITGB, 2930.0 m²/g and 1.5062 cm³/g). Besides, the physicochemical properties of MITGB and ITGB were also quite different including micro morphology, surface chemistry, functional groups, etc. In the experiment of removing organic pollutants with synthetic dye RhB and antibiotic TH as the models, MITGB showed excellent treatment ability. The maximum adsorption capacities of MITGB for RhB and TH were 1354.2 and 1462.6 mg/g, which were higher than most of the biochars. In addition, after five cycles of recycling, the adsorption capacities of the organic pollutant models can still be maintained at more than 80%, which showed high stability. This work verified the feasibility of microbial treatment to further improve the performance of biochar and provided a new idea and direction for exploring other biochars.

Solid Fe Resources Separated from Rolling Oil Sludge for CO Oxidation

The efficient recycling of valuable resources from rolling oil sludge (ROS) to gain new uses remains a formidable challenge. In this study, we reported the recycling of solid Fe resources from ROS by a catalytic hydrogenation technique and its catalytic performance for CO oxidation. The solid Fe resources, after calcination in air (Fe2O3-H), exhibited comparable activity to those prepared by the calcinations of ferric nitrate (Fe2O3-C), suggesting that the solid resources have excellent recycling value when used as raw materials for CO oxidation catalyst preparation. Further studies to improve the catalytic performance by supporting the materials on high surface area 13X zeolite and by pretreating the materials with CO atmosphere, showed that the CO pretreatment greatly improved the CO oxidation activity and the best activity was achieved on the 20 wt.%Fe2O3-H/13X sample with complete CO conversion at 250 °C. CO pretreatment could produce more oxygen vacancies, facilitating O2 activation, and thus accelerate the CO oxidation reaction rate. The excellent reducibility and sufficient O2 adsorption amount were also favorable for its performance. The recycling of solid Fe resources from ROS is quite promising for CO oxidation applications.

Performance and Mechanism of As(III/V) Removal from Aqueous Solution by Fe3O4-Sunflower Straw Biochar

Humans and ecosystems are severely damaged by the existence of As(III/V) in the aquatic environment. Herein, an advanced Fe₃O₄@SFBC (Fe₃O₄-sunflower straw biochar) adsorbent was fabricated by co-precipitation method with sunflower straw biochar (SFBC) prepared at different calcination temperatures and different SFBC/Fe mass ratios as templates. The optimal pH for As(III/V) removal was investigated, and Fe₃O₄@SFBC shows removal efficiency of 86.43% and 95.94% for As(III) and As(V), respectively, at pH 6 and 4. The adsorption effect of calcining and casting the biochar-bound Fe₃O₄ obtained at different temperatures and different SFBC/Fe mass ratios were analyzed by batch experiments. The results show that when the SFBC biochar is calcined at 450 °C with an SFBC/Fe mass ratio of 1:5, the adsorption of As(III) and As(V) reaches the maximum, which are 121.347 and 188.753 mg/g, respectively. Fe₃O₄@SFBC morphology, structure, surface functional groups, magnetic moment, and internal morphology were observed by XRD, FTIR, SEM, TEM, and VSM under optimal working conditions. The material shows a small particle size in the range of 12-14 nm with better magnetic properties (54.52 emu/g), which is suitable for arsenic removal. The adsorption mechanism of As(III/V) by Fe₃O₄@SFBC indicates the presence of chemisorption, electrostatic, and complexation. Finally, the material was used for five consecutive cycles of adsorption-desorption experiments, and no significant decrease in removal efficiency was observed. Therefore, the new adsorbent Fe₃O₄@SFBC can be efficiently used for arsenic removal in the aqueous system.

Cow Dung-Based Biochar Materials Prepared via Mixed Base and Its Application in the Removal of Organic Pollutants

Cow dung (CD) is a waste product of livestock production. Improper disposal of a large amount of CD will cause environmental pollution. In this work, three biochar materials based on CD (BMCD) were prepared by using three types of base, including KOH, NaOH, and mixed base (MB, a mixture of equal mass NaOH and KOH) as activators to investigate the different physicochemical properties of BMCDs (BMCD-K, BMCD-Na, and BMCD-MB). The objective was to verify the effectiveness of MB activation in the preparation of biochar materials. The results show that MB has an effect on the structural characteristics of BMCDs. In particular, the surface area and total pore volume, the specific surface area, and the total pore volume of BMCD-MB (4081.1 m² g⁻¹ and 3.0118 cm³ g⁻¹) are significantly larger than those of BMCD-K (1784.6 m² g⁻¹ and 1.1142 cm³ g⁻¹) and BMCD-Na (1446.1 m² g⁻¹ and 1.0788 cm³ g⁻¹). While synthetic dye rhodamine B (RhB) and antibiotic tetracycline hydrochloride (TH) were selected as organic pollutant models to explore the adsorption performances, the maximum adsorption capacities of BMCD-K, BMCD-NA and BMCD-MB were 951, 770, and 1241 mg g⁻¹ for RhB, 975, 1051, and 1105 mg g⁻¹ for TH, respectively, which were higher than those of most adsorbents. This study demonstrated that MB can be used as an effective activator for the preparation of biochar materials with enhanced performance.