Effective immobilization of bisphenol A utilizing activated biochar incorporated into soil: combined with batch adsorption and fixed-bed column studies

This study presented the mixture of biochar and soil for removal of bisphenol A (BPA) to assess environmental remediation ability. Using phoenix tree leaves as biomass and phosphoric acid as activator, after one-step hydrothermal and short-term activation, the eventual solid product was phosphoric acid hydrothermal activated carbon (HPC). The characterizations showed that HPC had the high specific surface (994.21 m2 & BULL;g-1), and large unsaturated esters and hydroxyl groups. The saturated adsorption capacities of batch and column adsorption for the addition of 0.5% HPC to soil were 0.790 mg & BULL;g-1 and 67.23 mg & BULL;kg-1, while to the natural soil were 0.236 mg & BULL;g-1 and 8.75 mg & BULL;kg-1, respectively. The adsorption kinetics and thermodynamic analysis indicated that the adsorption process utilizing HPC incorporated into soil was a chemical reaction rate-controlled, physical-dominated multilayer adsorption, and spontaneous endothermic. Also, batch adsorption experiments and analysis were performed under different pH levels, HPC contents, organic acid concentrations, and cationic strengths. Successively, fixed-bed column experiments were carried out with and without the HPC; the results showed that the wide mass transfer zone led to the effective fixation of BPA, and the organic acid had no obvious effect on the fixation of BPA when the 1.0% HPC mixed with soil. Finally, through characterizations and data analysis, the enhanced adsorption of BPA by HPC mixed with soil mainly relied on & pi;-& pi; interaction, hydrogen bonding, followed by electrostatic attraction and pore filling.

Automated summary

This study evaluated the environmental remediation ability of a mixture of biochar and soil for the removal of bisphenol A (BPA). The results showed that the phosphoric acid hydrothermal activated carbon (HPC) had a high specific surface area and large amounts of unsaturated esters and hydroxyl groups, allowing for effective adsorption of BPA. The study also investigated the effects of various factors on the adsorption process, and found that organic acids had no significant impact on the adsorption of BPA. Through characterization and data analysis, the enhanced adsorption of BPA by the HPC mixed with soil was mainly attributed to π-π interactions, hydrogen bonding, followed by electrostatic attraction and pore filling.