**7. Conclusion**

*Applications of Biochar for Environmental Safety*

heterogeneous processes.

Langmuir model.

Yao et al. [1] used these models to draw adsorption isotherm for phosphate on anaerobically digested sugar beet tailings. **Figure 9** shows that all models reproduced isotherm data correctly with correlation coefficients of 0.95. The highest adsorption capacity is presented by the Langmuir model at 133,085 mg/kg, while Freundlich and Langmuir-Freundlich models gave a better fit to the experimental data. It indicates that phosphate adsorption onto the biochar was determined by

Zhang et al. [40] ran isotherm models of phosphate adsorption on biochar and found that both Freundlich model and Langmuir model described the isotherm data well, while the Freundlich model had a better fit for the data as shown in **Figure 10**. The maximum adsorption capacity was 135,000 mg/kg according to the

**84**

**Figure 10.**

**Figure 9.**

*Adsorption isotherm for phosphate on biochar [1].*

*Adsorption isotherm for phosphate adsorption onto biochar AlOOH nanocomposite [40].*

Biomass conversion into pyrochar and hydrochar has seen a growing interest in the last years because of its use in different applications including phosphate adsorption from wastewater. Biochar has economic and sustainability benefits. In this chapter, an overview of hydrochar and pyrochar production techniques in addition to the application of biochar for phosphate adsorption from wastewater is discussed. Biochar needs to have adequate properties to be applied for phosphate adsorption from wastewater. Several factors influence the biochar properties including feedstock, pyrolysis temperature, solution pH, modification techniques, and treatment conditions. Studies have suggested that magnetic biochar has better adsorption properties than non-magnetic biochar. The biochar adsorption mechanisms are explained including ion exchange, electrostatic attraction, and chemical precipitation. Overall, biochar was proven to offer good phosphate adsorption rate along with environmental advantages such as low carbon emissions and renewability. However, further life cycle assessment studies of biochar with an evaluation of its economic benefits and environmental impacts are necessary for long-term applications.
