Damahe, et al (2024) BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More/Metal Nanoparticles-based Composites for Dye Remediation: A Review. Hybrid Advances. https://doi.org/10.1016/j.hybadv.2024.100254

Dyes are pervasive pollutants in water systems, originating from industries like textiles, cosmetics, and pharmaceuticals. These dyes can be harmful to both the environment and human health, causing issues such as carcinogenicity and ecological imbalance. Effective removal of dyes from wastewater is crucial, and various methods have been explored, including adsorption, a promising technique due to its efficiency and cost-effectiveness.

Biochar, a carbon-rich material derived from biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More, has gained attention as an effective adsorbent for dye removal. Its high surface area, porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More, and functional groups make it suitable for adsorption. When combined with metal nanoparticles, the adsorption capacity and efficiency of biochar are significantly enhanced. These biochar/metal nanoparticle composites leverage the strengths of both materials, leading to improved performance in dye remediation.

The process of adsorption involves the interaction between dye molecules and the adsorbent’s surface. This can occur through physical interactions, like van der Waals forces and hydrogen bonding, or chemical interactions, such as covalent bonding with functional groups on the adsorbent. The inclusion of metal nanoparticles on biochar enhances these interactions by increasing surface area and introducing catalytic properties, facilitating both adsorption and degradation of dye molecules.

Several studies highlight the effectiveness of biochar/metal nanoparticle composites in dye removal. For example, a composite of biochar loaded with Cu/Ni bimetallic nanoparticles demonstrated superior adsorption due to increased pore size and surface area. Another study showed that biochar modified with iron nanoparticles significantly improved the removal of methylene blue dye from water.

The adsorption process can be analyzed through various models to understand its kinetics and isotherms. Kinetic models, such as pseudo-first-order and pseudo-second-order, describe the rate of adsorption, while isotherm models, like Langmuir and Freundlich, explain the equilibrium relationship between the dye concentration and the amount adsorbed. Thermodynamic studies provide insights into the feasibility and energetics of the adsorption process, indicating whether the process is spontaneous and endothermic or exothermic.

Computational studies, including Density Functional Theory (DFT) and Response Surface Methodology (RSM), play a crucial role in optimizing the adsorption process. DFT helps in understanding the electronic interactions between dye molecules and adsorbents, while RSM aids in modeling and analyzing the effects of various parameters on the adsorption efficiency.

The sustainability of biochar/metal nanoparticle composites is further enhanced by their ability to be regenerated and reused. Regeneration techniques, such as thermal treatment and chemical washing, restore the adsorption capacity of the composites, making them a cost-effective solution for long-term use.

In conclusion, biochar/metal nanoparticle composites offer a sustainable and efficient method for dye remediation in wastewater. Their high adsorption capacity, combined with the benefits of metal nanoparticles, makes them a promising solution to tackle dye pollution. Future research should focus on optimizing the synthesis and regeneration processes, scaling up for industrial applications, and further exploring the environmental impacts of these composites to ensure they provide a viable long-term solution for water purification.