Prediction and optimization of adsorption performance of MC@MgAl-LDH for the removal of humic acid from aqueous solution: BBD model and mechanism

In this study, enteromorpha was used as a raw material, magnetic biochar (MC) was prepared by impregnation pyrolysis method. Enteromorpha magnetic biochar MgAl layered double hydroxide composite material (MC@MgAL-LDH) was then prepared by hydrothermal method for the adsorption study of removing humic acid (HA) from water. The effects of different influencing factors on the adsorption of HA by MC@MgAl-LDH were studied using BBD model. The results indicated that the adsorption process can be fitted well by the pseudo-second-order kinetic model and the Freundlich isotherm model. The maximum saturation adsorption capacity of MC@MgAl-LDH for HA was 5.85 mg g(-1) at 298.15 K. The absorbent was regenerated by thermal regeneration method, and the removal rate remained above 90% after 5 times of reuse. Electrostatic attraction and complexation were the main mechanisms for the removal of HA by MC@MgAl-LDH. Studies showed that the material presented excellent adsorption performance, pH wide adaptability and reusability.

Automated summary

In this study, enteromorpha magnetic biochar composite material was prepared and used for the removal of humic acid from water. Results showed that the material exhibited excellent adsorption performance and good reusability.