Author(s)

Yu Han^1,2, Yuming Yin¹, Hao Zhang^1,2, Sijing Sun^1,2, Zuzhi Huang^1,2, Yishu Deng^3*, Li Bao^1,2*

¹College of Resources and Environment, Yunnan Agricultural University, Kunming, China.
²Yunnan Soil Fertilization and Pollution Remediation Laboratory, Kunming, China.
³College of Building Engineering, Yunnan Agricultural University, Kunming, China.

Two major problems facing agriculture at present are soil pollution and the disposal of solid wastes generated during plant growth. The method of preparing biochar from solid wastes produced by plants is a means of maximizing the use of resources to combat the problem of soil pollution. In this study, we did not choose straw in the traditional sense but the waste branches from grape pruning, which has higher lignin cellulose, as the raw material. The biochar derived from grape branches pyrolyzed at 300˚C for two hours was utilized as a raw material to prepare modified biochar with varying concentrations of phosphoric acid. The adsorption performance and mechanism of Cd² were explored through experiments involving different concentrations, addition amounts, reaction times, kinetic analyses, and isothermal adsorption tests. The findings indicated that the optimal adsorption of Cd² occurred with a 20% phosphoric acid concentration, achieving the highest adsorption rate of 84.62%. At a dosage of 10 g/L, the maximum adsorption capacity reached 7.02 mg/g. The adsorption kinetics and isothermal adsorption of Cd² on biochar modified with 0.2% phosphoric acid (0.2 PB) closely followed the pseudo-first-order kinetics model (R² > 0.98) and the Freundlich model (R² > 0.97), respectively. This suggests that the adsorption process involves both physical and chemical mechanisms. SEM and FTIR analyses revealed that phosphoric acid modification primarily increased the biochar’s specific surface area and enhanced certain original functional groups. The adsorption process predominantly involved rapid ion diffusion and chemical adsorption, as confirmed by kinetic analysis and isothermal adsorption model analysis. In summary, the adsorption efficiency of 0.2 PB significantly improved, showing potential and feasibility for heavy metal remediation in soil. This supports the environmentally friendly concept of “treating waste with waste”.

Phosphate Modified, Grape Branch Biochar, Adsorbs, Cd

Han, Y. , Yin, Y. , Zhang, H. , Sun, S. , Huang, Z. , Deng, Y. and Bao, L. (2024) Adsorption Effect of Phosphate Modified Grape Branch Biochar on Cd² . Journal of Geoscience and Environment Protection, 12, 59-77. doi: 10.4236/gep.2024.124005.