In this study, we present a facile synthesis strategy for cylindrical iron‑carbon composites using red mud (RM) and corn straw (CS) to mitigate surface passivation and oxidation, enhancing their efficacy for CrVI and CuII removal from electroplating wastewater. Two composites were fabricated via optimized two-stage pyrolysis Fe3O4-BC (600 °C, CS:RM = 1:1) and ZVI-BC (800 °C, CS:RM = 1,3). Adsorption kinetics adhered to a pseudo-second-order model, while equilibrium data fit the Langmuir isotherm, confirming chemisorption-driven monolayer coverage. Maximum Langmuir capacities reached 25.6 mg/g (CrVI) and 281.6 mg/g (CuII) for Fe3O4-BC, and 49.6 mg/g (CrVI) and 319.4 mg/g (CuII) for ZVI-BC. An indirect regeneration method (external reducing agent + pyrolysis) significantly outperformed direct regeneration, sustaining >55 % (Fe3O4-BC) and > 70 % (ZVI-BC) removal efficiency over 5 cycles for both metal ions, versus <45 % with direct regeneration. Post-adsorption characterization (FTIR, XRD, XPS) identified removal mechanisms as electrostatic interaction, surface complexation, chemical reduction, and physisorption. DFT computations revealed ZVI-BC-OH as the optimal CrVI binding site (adsorption energy: −8.01 eV; adsorption distance: 5.53 Å). Despite reduced selectivity in real wastewater due to competing ions, both composites retained significant removal efficiency. Phytotoxicity and leaching tests validated the environmental safety for treated effluent and spent materials. This work presents a scalable approach to design cost-effective, reusable RM-based composites for CrVI/CuII-contaminated wastewater remediation.

Highly permselective and stable membranes are crucial to promoting the large-scale application of pervaporation (PV) in desalination. Despite the metal-organic frameworks (MOFs)-polymer composite membranes have demonstrated application potential, their desalination performance and structural stability remain constrained by poor MOF-polymer interfacial compatibility, as well as weak interfacial interaction between the separation layer and support layer. Here, we propose a dual-interface regulation strategy to construct a defect-free and stable two-dimensional (2D) ZIF-based composite membrane for high-performance PV desalination. Amino-functionalized 2D ZIF fillers with excellent dispersibility and a third component that covalently coordinates with both filler and polymer synergistically constructed a dense separation layer, effectively enhanced permeability and selectivity. Mussel-inspired polydopamine interlayer regulated the surface wettability of support layer and enhances its interfacial adhesion with separation layer to further enhance the permeability and structural stability. The composite membrane exhibited high water flux of 32.6 kg m-2 h-1 with almost complete salt rejection, demonstrating superior long-term operational stability and anti-fouling performance. Furthermore, the composite membranes also demonstrated application feasibility for natural seawater and industrial high-salinity wastewater, capable of continuously and simultaneously removing multiple ions from natural seawater. This work is expected to provide insights for further development of PV membranes with higher permeability and stability, and lay the foundation for expanding PV technology for sustainable industrial-scale desalination.

Sludge densification is a promising technology to enhance nutrient removal in existing municipal wastewater treatment plants (WWTPs). In this study, the graded-device hydrocyclone was installed into activated sludge system to assist sludge densification and disclose its microbial response mechanism. Higher nutrient removal (94.2 % for COD, 97.2 % for NH4+-N, 82.3 % for TN, 92.4 % for TP, respectively) were achieved in R2 reactor incorporating hydrocyclone, and these effluent indicators met the wastewater first class A discharge standards of China (GB18918-2002). The hydraulic shear forces of hydrocyclone promoted the sludge transformation from loose flocs to dense particles (average size of 292 mu m), sludge settleability (relative hydrophobicity of 79.1 %, SVI30 of 60 mL/g), and the secretion of extracellular polymeric substances (EPS of 98.89 mg/g-SS, protein/ polysaccharide ratio of 1.78). Ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, denitrifying bacteria and polyphosphate-accumulating organisms were effectively enriched. These functional bacteria actively participated in membrane transport, signal transduction, carbon metabolism, nitrogen metabolism, phosphonate and phosphinate metabolism, providing the core driving force for long-term stable nutrient removal. These findings provided feasibility and mechanism support for hydrocyclone in enhancing nutrient removal, with a view to achieving cost reduction and efficiency benefits via sludge densification in industrial applications at full-scale WWTPs within the environmental field.

Although conventional chemical fertilizers enhance crop yields, their use is associated with significant environmental degradation and high economic costs. Biochar derived from organic residues has emerged as an important carbon input to soils and provides multiple functional benefits. Biochar-based slow-release organic fertilizers (BCSROFs) offer the potential to mitigate environmental pressures by improving soil properties. While considerable attention has been given to biochar-based slow-release fertilizers (BCSRFs) regarding nutrient loading and release behavior, comprehensive assessments of biochar's influence on soil pH remain limited. This gap contributes to ongoing uncertainty about its performance across diverse environmental and management settings. Furthermore, the capacity of BCSROFs to improve soil physical conditions in both alkaline and acidic soils remains a subject of debate, and the underlying mechanisms governing biochar’s behavior are not yet fully clarified. This review synthesizes current knowledge on the development, synthesis, and application of BCSROFs, with emphasis on their role in ameliorating saline and acidic soils, their economic feasibility, and the mechanisms tentatively proposed to explain their function. Based on available technical, environmental, and economic evidence, the application of BCSROFs is strongly recommended as a viable and promising approach to improving soil quality and advancing sustainable agricultural practices.

Herein, a “waste-treats-waste” sustainable strategy was developed to achieve deep fluoride removal through the synergistic utilization of industrial and agricultural waste. The alkaline leachate of waste red mud (RM) was innovatively employed as a chemical alkaline alternative for pretreating wheat straw, which was subsequently modified with lanthanum (La) to prepare a novel high-performance adsorbent (denoted as La-RWSB). The adsorption behaviors of fluoride ions on La-RWSB were systematically evaluated under varying conditions. Adsorption data conformed to Pseudo-second-order kinetic model and Langmuir isotherm model, indicating the adsorption process was monolayer chemisorption, while thermodynamic analysis confirmed its spontaneous nature. The maximum adsorption capacity of La-RWSB was 65.12 mg/g at 313 K. The underlying mechanism was elucidated via determination of the point of zero charge, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), which revealed that fluoride removal primarily involved electrostatic interaction, ion exchange, and complex precipitation. Notably, La-RWSB achieved residual fluoride concentration of 0.96 mg/L and a fluoride removal of 91.94% in actual industrial wastewater (C0 = 12 mg/L and dosage = 1 g/L). This work highlights the potential of La-RWSB as a sustainable solution for valorizing solid wastes and advanced fluoride remediation.

In this study, we report cylindrical iron-carbon materials namely Fe3O4-BC and ZVI-BC, developed through a two-stage pyrolytic reduction of red mud using corn straw at 600 degrees C and 800 degrees C, respectively. Their performance was evaluated for removing cationic (Gentian Violet, GV; Methylene Blue, MB) and anionic (Methyl Orange, MO) dyes. ZVI-BC exhibited superior Langmuir maximum capacities of 556.1 mg/g (GV), 388.8 mg/g (MB), and 151.1 mg/g (MO), significantly outperforming Fe3O4-BC (405.9, 267.7, and 100.6 mg/g). The removal process followed pseudo-second-order kinetics, with mechanisms involving monolayer chemisorption and internal diffusion. UV-Vis spectroscopy revealed synergistic adsorption-reduction for GV, while MB and MO were removed primarily via adsorption. Post-treatment characterization using FTIR, XRD, and XPS revealed key interactions, including electrostatic attraction, hydrogen bonding, it-it interactions, and chemical reduction. Density functional theory (DFT) computations revealed ZVI-BC-OH as optimal interfacial binding site for GV (adsorption energy of -1.9 eV and distance of 4.5 angstrom). Coexisting ions (Na+, Mg2+, NO3 , PO43 ) induced only a minimal reduction (1.0-6.0 mg/g) in cationic dyes removal. Biomass-assisted regeneration maintained similar to 90 % capacity over five cycles with minimal weight loss (similar to 4.0 %). Techno-economic analysis demonstrated cost-effectiveness (similar to 1.06 $/kg), moderate energy consumption (similar to 21 MJ/kg), and low carbon footprint (similar to 2.7 kg CO2-eq/kg) establishing this material development approach as a scalable and sustainable solution for dye-contaminated wastewater treatment.

Biomass, the world’s fourth-largest energy source, is a renewable and sustainable resource for diversifying the global energy supply. Pyrolysis is a promising thermochemical conversion technology that rapidly transforms biomass into bio-oil, a valuable liquid product capable of yielding high-value chemicals and fuels. Nevertheless, the conventional reactors hinge on their bio-oil production efficiency and high energy costs. We propose a skid-mounted biomass pyrolysis plant designed to overcome these limitations. In addition, the complex and impure nature of crude bio-oil from the conventional conversion of biomass to bio-oil, characterized by a high content of reactive oxygenated compounds, necessitates effective separation and upgrading to enable its practical application. This review also examines the current state of biomass pyrolysis-to-oil technology. It explores advancements in pyrolysis processes and reactor designs, providing a global perspective on their development and scalability. A significant focus is placed on the critical challenge of bio-oil refining, where we present a detailed analysis of the leading separation technologies, including physical and chemical refining and separation techniques, distillation, membrane separation, chromatographic, and supercritical extraction methods. We evaluate their respective advantages, limitations, and potential for industrial implementation. By synthesizing this information, the review provides an assessment of the pathway to commercializing bio-oil. It concludes that while significant progress has been made, strategic integration of separation processes and targeted catalyst development are essential to overcome existing technical and economic barriers, ultimately unlocking the full potential of bio-oil as a sustainable source of fuels and chemicals.

The global aluminum industry generates over 200 million tons of highly alkaline red mud (RM). This has led to 4 billion tons of hazardous stockpiles, yet the current annual recycling rate remains below 8 %. This underutilization is particularly striking given its potential as a valuable source of iron. However, conventional iron recovery methods are often energy-intensive or environmentally damaging. Here, we present a sustainable and additive-free strategy using wheat straw (WS) as a reductant to recover iron from challenging low-iron RM (28.69 wt% Fe). We compared this biomass-based approach with conventional reductants, activated carbon (AC) and graphite (GP), and identified distinct reduction pathways: WS and AC facilitated indirect reduction at <= 1000 degrees C, while GP required temperatures >= 1100 degrees C for direct reduction. A Life-Cycle Assessment (LCA) confirmed that the WS process achieved an optimal balance of performance and sustainability. It achieved 72 % of iron recovery at a grade of 77 %, while slashing production costs to-$0.81/kg Fe and reducing CO2 emissions to just-1.6 kg CO2-eq/kg Fe. In contrast, while AC yielded a higher iron recovery (76 %) and grade (81 %), it did so at a prohibitive cost of-$23/kg Fe and with a significantly larger carbon footprint (-34 kg CO2-eq/kg Fe). GP remained inconsistent, yielding a low iron grade at higher cost and emissions. This work establishes WS as a closed-loop solution that not only detoxifies an industrial waste but also provides a scalable and sustainable pathway for iron production, transforming an environmental liability into a high-value resource.

In this study, the pyrolytic reduction of iron oxides contained in red mud using biomass-derived reductive gases was explored. Wheat straw and rice husk were evaluated together with activated carbon and graphite for their effectiveness in converting iron oxides to magnetite. Thermodynamic analyses using thermogravimetric-mass spectrometry (TG-MS) demonstrated that CO, H2, CH4, and biochar could effectively reduce iron oxides, with CO being particularly effective at lower temperatures. Optimal parameters for iron recovery were identified through an orthogonal experimental design, highlighting wheat straw as the superior biomass feedstock due to its high yield of reducing gases and fast reduction kinetics. Single-factor optimization emphasized the importance of temperature and red mud-to-biomass ratio. Optimization of pyrolytic reduction conditions revealed that wheat straw achieved the highest iron recovery rate of 75 % and a concentrate grade of 42 % at 550 degrees C, with a red mudto-wheat straw ratio of 1:2, a heating rate of 12 degrees C/min, and a reduction time of 40 min. Mechanistic studies using X-ray diffraction, X-ray fluorescence, and scanning electron microscopy showed hematite in red mud transforming into magnetite, with some aluminum atoms substituting for iron to form iron-aluminum spinel, impacting the concentrate grade. This is a promising method for recycling iron from red mud, mitigating environmental impact, and conserving resources.

Red mud, a byproduct of aluminium production, poses serious environmental risks due to its high alkalinity and large volume. This study explores the synthesis of two iron-carbon adsorption-reaction materials (Fe-C ARMs), Fe3O4-BC and ZVI-BC, using corn straw (CS) and red mud (RM) through biomass pyrolytic reduction. CS serves as a pore-forming and reducing agent, while RM acts as the iron precursor. We explored the impact of various preparation conditions, including the raw CS to RM ratio (2:1-1:4), pyrolysis time (45-120 min), and temperature (400 degrees C to 600 degrees C for Fe3O4-BC, and 700 degrees C to 1000 degrees C for ZVI-BC), on the characteristics of the Fe-C ARMs. Response Surface Methodology (RSM) identified optimal conditions: for Fe3O4-BC, a CS to RM ratio of 1:1, 600 degrees C pyrolysis temperature, and 75 minutes; for ZVI-BC, a CS to RM ratio of 1:3, 912 degrees C pyrolysis temperature, and 75 minutes. Maximum dye removal capacities were 342.4 mg/g for GV and 145.4 mg/g for MO with Fe3O4-BC, and 480.5 mg/g for GV and 215.1 mg/g for MO with ZVI-BC. The synthesis mechanisms and physiochemical characteristics of the Fe-C ARMs synthesized under optimal conditions were analyzed using TGA/DTA, FE-SEM coupled with EDS, FTIR, XRD, XPS and BET surface area analysis. The removal of dyes by Fe-C ARMs occurs via a combination of adsorption and reduction on carbon and iron oxides, with efficiency varying according to experimental conditions. Additionally, the materials exhibited reusability over five operational cycles, suggesting their potential for sustainable wastewater treatment applications.

Superwetting membranes that exhibit distinct affinities towards water and oil hold immense promise for the removal of oil from wastewater. However, the coexistence of water-soluble pollutants and insoluble oil in real emulsified oily wastewater systems significantly escalates the complexity of purifying such wastewater. It is still a big challenge to simultaneously remove multi-component pollutants from real wastewater. Therefore, the development of superwetting separation membranes capable of both oil and pollutants is crucial for purifying multi-component emulsified oily wastewater. In this work, we developed a PDA@ZIF-8/Nylon composite membrane via vacuum-filtering polydopamine-coated ZIF-8 nanoparticles onto nylon substrate membrane for multi-component emulsified oily wastewater purification. The introduction of polydopamine-modified ZIF-8 nanoparticles endowed the composite membrane with underwater superoleophobicity and negative surface charges, which facilitates the superwettability-induced oil removal and electrostatic interaction-mediated pollutants removal. The composite membrane exhibited excellent oil removal performance for various emulsifier-stabilized O/W emulsions with excellent recyclability and continuous separation performance. In addition, the oil and dye in the dye emulsion were simultaneously removed. Further application potential studies found that the removal and reduction of Au (III) from gold-containing wastewater was achieved based on phenolic hydroxyl groups on the membrane surface, extending the application of membrane separation technology for gold recovery. It was worth mentioning that the composite membranes exhibit excellent antifouling ability, long-term stability, chemical stability, and light-induced self-cleaning properties. This work offers new insights into fabricating superwetting membranes for multi-component emulsified oily wastewater purification.

Desalination Brine discharge management is typically based on laboratory test data; however, the resilience of marine ecosystems may alter the actual ecological effects once the brine is discharged into the sea. In this context, it is necessary to reconsider whether the current management measures for brine discharge are overly stringent. This study summarizes the sources of ecological risk factors in desalination brine, compares toxicological findings from laboratory tests and field investigations, and analyzes the discrepancies between them from the perspectives of testing methodology, test results, and desalination process design. Laboratory toxicity tests often predict greater ecological risks than actual impacts because they assume constant exposure and near-perfect baseline survival, overlooking natural stressors, tidal dilution, and species’ adaptive responses. Conversely, field observations may underestimate actual impacts because most surveyed desalination plants have already implemented impact-control measures. These findings highlight the importance of integrating both laboratory and field data to develop more balanced and effective brine discharge management strategies.

The co-discharge of brine and cooling water is widely regarded as a preferred method for desalination brine disposal. However, existing research on the effectiveness of this approach primarily relies on software simulations, with limited studies addressing its impact in real marine environments. This study conducted a field investigation to evaluate the effects of co-discharge of brine and cooling water on water quality, plankton, and macrobenthic organisms in the receiving marine ecosystem. Two discharge scenarios were examined: a low mixing ratio (brine comprising 10% of the total discharge volume) and a high mixing ratio (brine comprising 50% of the total discharge volume). The results demonstrated that the combined discharge of brine and cooling water influences not only temperature and salinity but also other water quality parameters. Mixing ratios significantly affected pH, water temperature, salinity, and aluminum (Al) concentrations in the receiving waters. In the high mixing ratio discharge area, pH and salinity increased by 2.4% and 3.1%, respectively, whereas temperature and Al concentration decreased by 5.1% and 43.8%, respectively. Phytoplankton abundance and species number decreased by 90% and 50%, respectively, near the low mixing ratio outlet, but increased by 96% and 28%, respectively, near the high mixing ratio outlet. In contrast, no obvious differences were observed in zooplankton species composition, abundance, or diversity index between the two discharge areas. The findings of this study provide new insights into the selection of discharge methods and brine discharge management.

Nano zero-valent iron (nZVI) is a promising technology for the remediation of both organic and inorganic pollutants in groundwater and wastewater. Despite its potential, there are several limitations of as-prepared nZVI particles, including surface passivation, agglomeration, reduced mobility, and reactivity in subsurface environments, as well as pH sensitivity. This comprehensive review aims to address these limitations by evaluating different nZVI production techniques in terms of their intrinsic properties, such as particle size and surface area, and their implications. Furthermore, practical limitations associated with as-prepared nZVI particles are described, and potential countermeasures are discussed. These countermeasures include pretreatment methods such as acid washing, hydrogen gas, liquid nitrogen activation, and coupling with weak magnetic force, as well as surface modification methods such as metal coupling, sulfidation, polymer, surfactant, and cellulose coating, emulsification, and support with other adsorbent materials. The review also provides examples of pilot-scale and field-scale applications of nZVI particles. Overall, the review offers a comprehensive overview of nZVI synthesis methods and their implications for production processes. The strategies presented for improving the reactivity and performance of nZVI particles in practical applications are valuable for researchers and practitioners in the field of environmental remediation.

Red mud, a byproduct of alumina production, presents significant challenges due to its large-scale production and inefficient utilization, leading to substantial environmental and health hazards. Traditional disposal methods, such as land-based stockpiling, exacerbate environmental degradation, including soil and groundwater contamination, air pollution, and associated health risks. However, red mud, rich in valuable metals, particularly iron, offers a secondary resource for value-added utilization. This review evaluates various iron extraction methods, including physical, chemical, and pyrometallurgical techniques. Physical methods like magnetic separation and flotation, alongside chemical and hydrometallurgical methods like acid leaching, often encounter obstacles such as low iron recovery rates and acidic wastewater generation. Pyrometallurgical methods, despite their effectiveness, are hindered by high energy consumption and environmental concerns. Conversely, biomass pyrolytic reduction followed by magnetic separation within pyrometallurgical methods has emerged as a promising alternative. However, significant gaps remain in understanding the transformation mechanisms of iron minerals and impurities during biomass pyrolytic reduction, the kinetics of reduction specific to red mud, optimizing biomass quantities, and the nature of produced pyrolytic gases. Addressing these gaps is essential for realizing the full potential of biomass pyrolytic reduction as a sustainable solution for iron extraction from red mud, mitigating environmental impact and fostering sustainability.

The impact of desalination brine on the marine environment is a global concern. Regarding this, salinity is generally accepted as the major environmental factor in desalination concentrate. However, recent studies have shown that the influence of organic contaminants in brine cannot be ignored. Therefore, a non-targeted screening method based on comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry (GC × GC-qMS) was developed for identifying organic contaminants in the desalination brine. A total of 404 compounds were tentatively identified from four seawater desalination plants (three reverse osmosis plants and one multiple effect distillation plant) in China. The identified compounds were prioritized based on their persistence, bioaccumulation, ecotoxicity, usage, and detection frequency. Twenty-one (21) compounds (seven phthalates, ten pesticides, four trihalomethanes) were then selected for further quantitative analysis and ecological risk assessment, including compounds from the priority list along with substances from the same chemical classes. Ecologically risky substances in brine include diisobutylphthalate and bis(2-Ethylhexyl) phthalate, atrazine and acetochlor, and bromoform. Most of the contaminants come from raw seawater, and no high risk contaminants introduced by the desalination process have been found except for disinfection by-products. In brine discharge management, people believed that all pollutions in raw seawater was concentrated by desalination process. This study shows that not all pollutants are concentrated during the desalination process. In this study, the total concentration of pesticide in the brine increased by 58.42%. The concentration of ∑PAEs decreased by 13.65% in reverse osmosis desalination plants and increased by 10.96% in the multi-effect distillation plant. The concentration of trihalomethane increased significantly in the desalination concentrate. The change in the concentration of pollutants in the desalination concentrate was related to the pretreatment method and the chemical characteristics of the contaminants. The method and results given in this study hinted a new idea to identify and control the environmental impact factors of brine.

Sodium alginate (SA) biopolymer has been recognized as an efficient adsorbent material owing to their unique characteristics, including biodegradability, non-toxic nature, and presence of abundant hydrophilic functional groups. Accordingly, in the current research work, UiO-66-OH and UiO-66-(OH)(2) metal organic framework (MOF) nanoparticles (NPs) have been integrated into SA biopolymer-based three-dimensional (3-D) membrane capsules (MCs) via a simple and facile approach to remove toxic metal cations (Cu2+ and Cd2+) from water and real sewage. The newly configured capsules were characterized by FTIR, SEM, XRD, EDX and XPS analyses techniques. Exceptional sorption properties of the as-developed capsules were ensured by evaluation of the pertinent operational parameters, i.e., contents of MOF-NPs (1-100 wt%), adsorbent dosage (0.001-0.05 g), content time (0-360 h), pH (1-8), initial concentration of metal cations (5-1000 mg/L) and reaction temperature (298.15-333.15 K) on the eradication of Cu2+ and Cd2+ metal cations. It was found that hydrophilic functional groups (-OH and -COOH) have performed an imperative role in the smooth loading of MOF-NPs into 3-D membrane capsules via intra/inter-molecular hydrogen bonding and van der waals potencies. The maximum monolayer uptake capacities (as calculated by the Langmuir isotherm model) of Cd2+ and Cu2+ by 3-D SGMMCs-OH were 940 and 1150 mg/g, respectively, and by 3-D SGMMCs-(OH)(2) were 1375 and 1575 mg/g, respectively, under optimum conditions. The as-developed capsules have demonstrated superior selectivity against targeted metal cations under designated pH and maintained >80 % removal efficiency up to six consecutive treatment cycles. Removal mechanisms of metal cations by the 3-D SGMMCs-OH/(OH)(2) was proposed, and electrostatic interaction, ion-exchange, inner-sphere coordination bonds/interactions, and aromatic ligands exchange were observed to be the key removal mechanisms. Notably, FTIR and XPS analysis indicated that hydroxyl groups of Zr-OH and BDC-OH/(OH)(2) aromatic linkers played vital roles in Cu2+ and Cd2+ adsorption by participating in inner-sphere coordination interactions and aromatic ligands exchange mechanisms. The as-prepared capsules indicated >70 % removal efficiency of Cu2+ from real electroplating wastewater in the manifestation of other competitive metal ions and pollutants under selected experimental conditions. Thus, it was observed that newly configured 3-D SGMMCs-OH/(OH)(2) have offered a valuable discernment into the development of MOFs-based water decontamination 3-D capsules for industrial applications.

Microplastics (MPs) and nanoplastics (NPs) have been discovered in diverse environmental milieux, and they have attracted much attention due to their possible toxicological impacts on living organisms. Likewise, salts, organic chemicals, heavy metals, natural organic matter, and other biomolecules are ubiquitously in the ecosystem. In a natural environment, MPs and NPs can interact with natural organic matter and biomolecules because of their exceptional characteristics. They can develop corona-based complexes, including eco-corona (EC) or bio-corona (BC) on the surface of MPs and NPs that not only change physiochemical characteristics but also its fate, distribution, uptake, transportation, biotransformation, and toxicological performance. Unlike orthodox toxins, coronas-based complexes on MPs and NPs rather than pristine MPs/NPs may be more hazardous. Therefore, the current critical review aims to discuss the up-to-date status of the modulations in the toxicological behavior of coronas-based MPs and NPs complexes on different environmental species. Significantly, it also focuses on the factors affecting the modulations of toxicological behavior of eco- and bio-corona-based MPs and NPs complexes for better understanding the role of environmental variables on the toxicity of plastics particles. Furthermore, this review systematically highlighted that the effect of a coronas-based complexes on the toxicological behavior of MPs and NPs is multifarious and variable in terms of plastic particle sizes, biomolecule’s types, polymer types, environmental species, and designed experimental conditions. To sum up, the current review addresses existing knowledge gaps and suggests recommendations.

This study investigates the potential of biochar produced via a solar pyrolysis system and its effectiveness in removing copper (Cu2+) ions from water, presenting a sustainable and energy-efficient method for biochar production and biomass recycling. Two common agricultural and livestock wastes, corn straw and cow dung, were used as raw materials to produce biochar. These materials underwent solar pyrolysis under limited oxygen conditions to produce biochar, which was then compared to biochar produced via traditional pyrolysis. The comparison involved elemental analyses, infrared spectroscopy, scanning electron microscopy, and specific surface area and pore size analysis to highlight differences in their physical and chemical properties. Adsorption experiments were conducted to evaluate the adsorptive capacity of biochar for copper ions (Cu2+) from water, determining the optimal pH conditions and underlying adsorption mechanisms. The findings reveal that biochar produced through solar pyrolysis exhibits similar properties and Cu2+ adsorption capacities to those prepared by traditional methods. Specifically, cow dung biochar demonstrated a higher adsorption capacity for Cu2+ compared to corn straw biochar. The Cu2+ adsorption by corn straw biochar followed the Langmuir isothermal adsorption model and pseudo-second-order kinetic equation, whereas cow dung biochar conformed to the Freundlich isothermal adsorption model and pseudo-second-order kinetic equation. By demonstrating the comparable efficacy of solar pyrolysis biochar in heavy metal adsorption, this study highlights its potential for sustainable environmental remediation and biomass utilization.

Biochar production through slow pyrolysis is a versatile and adaptable approach for managing diverse biomass waste. However, their industrial applications remain limited because of their high energy consumption and the emission of toxic gases. Solar-biomass pyrolysis systems have been proposed to address these challenges. This review examines the relationship between output configuration and the adaptability of slow and solar-biomass pyrolysis systems for biochar production. Studies have revealed that the average heat energy required for thermal conversion of biomass to biochar ranges from 1.94 to 2.67 kJ/kg K can be achieved through both conventional and solar pyrolysis routes. Solar pyrolysis demonstrates maximum power and flux density of 1.5 kW and 12,000 kW/m 2 , respectively, aligning with the power and temperature range of conventional slow pyrolysis. Moreover, solar pyrolysis emits approximately 58.89% less CO 2 as compared to the conventional electrical heating-based pyrolysis. Despite these advantages, the market implementation of solar-biomass pyrolysis systems is limited, necessitating the resolution of various barriers for commercial applications. The current review concludes by providing future recommendations, emphasizing the development of an eco-friendly solar-biomass pyrolysis system for large-scale biochar production.