Abstract

Environmental pollution, driven by industrial, agricultural, and urban activities, poses severe risks to ecosystems and human health. The increasing amount of contaminants in soil and water has needed the exploration of innovative remediation technologies that can effectively address these challenges. MOFs, Biochar & Carbon Nanocomposites used for Pollution Treatment This review makes insights from advanced remediation technologies focusing on MOFs; biochar; carbon nanocomposites, activated carbon, and metal-organic frameworks (MOFs). These materials, often modified to enhance their adsorption and catalytic properties, have shown significant potential in addressing a wide range of pollutants including heavy metals, organic contaminants and nutrients.

Biochar, derived from the pyrolysis of biomass, not only serves as an effective adsorbent but also improves soil health and fertility when applied to agricultural lands. Activated carbon is renowned for its high surface area and porosity, making it a versatile material for water treatment applications. MOFs, with their unique crystalline structures and tunable functionalities, offer unprecedented capabilities for targeted pollutant capture and degradation.

This unified analysis(MOFs; biochar; carbon nanocomposites) highlights their mechanisms of action, diverse applications across different environmental matrices, and future prospects in the field of environmental remediation. By bridging gaps in existing literature and identifying synergies among these materials, this review aims to suggest pathways for integrated solutions that can enhance the efficacy of pollution treatment strategies(e.g. water &soil) while promoting sustainability in environmental management practices

1. Introduction

Pollution of soil, water, and air remains one of the most pressing global environmental challenges. Heavy metals, emerging pollutants (EPs), and volatile organic compounds (VOCs) are persistent contaminants that resist degradation through conventional remediation techniques. These pollutants are everywhere spreading through industrial waste, farm runoff, and growing cities, making their harmful effects on both the environment and human health even more severe. For instance, arsenic and antimony contamination in soils has been linked to mining activities, while pharmaceuticals and endocrine disruptors in water bodies are byproducts of inadequate wastewater treatment systems (Bolan et al., 2022; James et al., 2012).they are treated with MOFs, Biochar & Carbon Nanocomposites for Pollution Treatment

Recent advancements in materials science have identified innovative solutions to combat these pollutants effectively. Among these, MOFs; biochar; carbon nanocomposites, activated carbon, and metalorganic frameworks (MOFs) stand out as promising tools due to their high surface areas, tunable properties, and multifunctional capabilities. Biochar and activated carbon, derived from biomass and carbon-rich materials, have been extensively employed for adsorptive removal of heavy metals and organic pollutants. Similarly, MOFs, composed of metal ions coordinated to organic ligands, offer unparalleled versatility in adsorptive and catalytic applications (Li et al., 2019; Rao et al., 2023).

This review unifies insights from recent studies to present a comprehensive understanding of these materials’ applications in soil, water, and air pollution treatment. The integration of biochar, activated carbon, and MOFs into hybrid systems offers synergistic advantages, enabling simultaneous removal of diverse contaminants. Such approaches not only enhance remediation efficiency but also address limitations associated with individual technologies, paving the way for sustainable environmental management strategies.

2. Soil Remediation Techniques

2.1 Use of Biochar and Activated Carbon

Soil contamination with arsenic (As) and antimony (Sb) is a significant issue, especially in areas affected by mining and industrial activities. Fe/Mn-modified biochar and activated carbon have demonstrated effective stabilization of these contaminants by enhancing adsorption and reducing their mobility (Bolan et al., 2022; Wan et al., 2020).

Mechanisms:

Fe and Mn modifications increase the surface area and introduce active sites for metal binding.

These materials enhance soil pH, soil organic matter (SOM), and enzyme activities, improving overall soil health (Ghassemi-Golezani & Farhangi-Abriz, 2021).

Table: 1 Comparison of Biochar and Activated Carbon:

ParameterBiocharActivated CarbonSource materialBiomassCarbon-rich materialsSurface areaModerateHighAdsorption efficiencyModerate to highHighModifications requiredFe/Mn for enhancementFe/Mn for specific needs

Fig.1 Source: Bioeconomy Solutions.MOFs, Biochar & Carbon Nanocomposites.

2.2 Integration with MOFs

While biochar and activated carbon are effective, MOFs offer additional benefits, such as superior adsorption capacity and catalytic functionalities. MOFs could complement these materials by immobilizing contaminants through reactive oxygen species (ROS) generation and complexation mechanisms (Yang et al., 2024).

Table:2 Examples of Integrated Systems:

Hybrid SystemTaget ContaminantMechanismMOF-BiocharArsenic, CadmiumAdsorption, ROSMOF-Activated CarbonLead, AntimonyAdsorption, Complexation

Fig.2 Source: Bioeconomy Solutions MOFs, Biochar & Carbon Nanocomposites.

3. Water Pollution Control with MOF

3.1 Emerging Organic Pollutants (EPs)

EPs, including pharmaceuticals, endocrine disruptors, and industrial chemicals, are challenging to remove using conventional water treatment methods. MOFs and their composites, such as ZnO-biochar and TiO₂-biochar, have emerged as potent solutions for EP degradation (Kumar et al., 2020).

Key Features:

• MOFs exhibit high porosity and tunable active sites, enabling efficient adsorption and catalytic degradation.
• Photocatalysis, involving ROS generation under light irradiation, is a primary mechanism for EP removal (James et al., 2012).

Table: 3 Comparison of MOFs for EP Treatment:

MOF MaterialKey Properties ApplicationsZnO-BiocharHigh surface areaPharmaceutical removalTiO₂-BiocharVisible light activationEndocrine disruptorsCeO₂-BiocharCatalytic efficiencyIndustrial pollutants

Fig.3: comparasion of Biochar MOFs, Biochar & Carbon Nanocomposites.

3.2 MOFs-Biochar Nanocomposites

Integrating MOFs with biochar enhances stability and reusability. Examples include:

ZnO-biochar for pharmaceutical degradation.

TiO₂-biochar for visible-light-driven degradation of industrial chemicals (Li et al., 2024).

Table: 4

Composite MaterialPollutant Removal RateDurabilityZnO-Biochar85%HighTiO₂-Biochar90%ModerateCeO₂-Biochar80%High

3.2 MOFs-Biochar Nanocomposites

Integrating MOFs with biochar enhances stability and reusability. Examples include:

• ZnO-biochar for pharmaceutical degradation.
• TiO₂-biochar for visible-light-driven degradation of industrial chemicals (Li et al., 2024).

Characterization techniques like FTIR, SEM, and XPS have validated these composites’ structural and functional properties, confirming their effectiveness in EP treatment.

4. Air Pollution: VOC Degradation

4.1 VOC Challenges and MOF Solutions

Volatile organic compounds (VOCs) are significant contributors to urban air pollution. MOF-based catalysts, particularly those modified with metals or dopants, provide sustainable solutions for VOC degradation through mechanisms like photocatalysis, thermal catalysis, and plasma catalysis (Rao et al., 2023).

4.2 Catalytic Processes

• Photocatalysis: MOFs such as TiO₂-UiO-66-NH₂ degrade VOCs like toluene under visible light (Chen & Liu, 2021).

• Thermal Catalysis: CeO₂-MOFs leverage oxygen vacancies to facilitate VOC breakdown at moderate temperatures (Zhang et al., 2020).
• Plasma Catalysis: MOF-supported metal oxides degrade VOCs at room temperature, reducing energy requirements (Sun et al., 2021).

5. Convergence of Technologies

Combining biochar, activated carbon, and MOFs into hybrid composites presents a synergistic approach to environmental remediation. These materials’ complementary properties enable multi-pollutant treatment across soil, water, and air, providing an integrated solution for complex contamination scenarios.

6. Future Directions

6.1 Research Priorities

• Stability and Scalability: Developing durable and cost-effective materials for large-scale applications.
• Mechanistic Insights: Further exploration of molecular mechanisms underlying pollutant degradation.
• Hybrid Systems: Advancing composite materials that integrate MOFs, biochar, and activated carbon for enhanced performance.

6.2 Practical Applications

• Deployment MOFs ; biochar; carbon nanocomposites in industrial wastewater treatment.
• Adoption in urban air quality improvement programs.
• Use in agricultural soil remediation to enhance crop productivity.

References

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• Wan, X., Li, C., & Parikh, S.J. (2020). Simultaneous removal of arsenic, cadmium, and lead from soil by iron-modified magnetic biochar. Environmental Pollution, 261, 114157.

• Ghassemi-Golezani, K., & Farhangi-Abriz, S. (2021). Biochar-based metal oxide nanocomposites of magnesium and manganese improved root development and productivity of safflower under salt stress. Rhizosphere, 19, 100416.

• James, S. L., Adams, C. J., Bolm, C., et al. (2012). Mechanochemistry: Opportunities for new and cleaner synthesis. Chemical Society Reviews.

• Kumar, M., Xiong, X., Wan, Z. (2020). Ball milling as a mechanochemical technology for novel biochar nanomaterials. Bioresource Technology.

• Rao, R., et al. (2023). Recent advances of metal-organic framework-based and derivative materials in the heterogeneous catalytic removal of volatile organic compounds. Journal of Colloid and Interface Science, 636, 55-72.

• Zhang, X., et al. (2020). Oxygen vacancies in MOF-derived metal oxides for VOC combustion. Applied Catalysis B: Environmental, 268, 118485.

• Sun, L., Zhao, M., & Li, J. (2021). Synthesis and modification of MOFs for VOC degradation. ACS Sustainable Chemistry & Engineering, 9(4), 1428-1436.

• Li, Z., et al. (2019). Doped MOFs in selective oxidation reactions: A review. Journal of Materials Chemistry A, 7(20), 12652-12668.

Chen, Y., & Liu, N. (2021). Photocatalytic

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