Preparation of activated sludge based biochar modified with phosphoric acid and its treatment of lead containing wastewater
The pollution of lead[Pb(Ⅱ)]to water resources is more and more serious.Finding efficient and low-cost adsorbents has been a difficult problem.In this study,two kinds of solid wastes,sludge and Radix isatidis residue,were used to prepare biochar by co-pyrolysis.In order to enhance the adsorption of lead ions in wastewater,the biochar was modified with phosphoric acid(H3PO4).SEM images showed that the pore structure of the modified biochar became more devel-oped and the specific surface area increased.The results of EDS spectra indicate that there may be cation exchange in the process of Pb(Ⅱ)adsorption by modified biochar in wastewater.FTIR,XRD and XPS analysis showed that there may be complexation and co-precipitation during the ad-sorption of Pb(Ⅱ)from wastewater by modified biochar.The results of adsorption kinetics experi-ment showed that R2 of pseudo-first-order kinetic model,pseudo-second-order kinetic model and Elovich model were all greater than 0.99,indicating that physical and chemical adsorption played an important role in the removal of Pb(Ⅱ)from modified biochar.Adsorption isotherm analysis showed that the adsorption capacity n in this study was greater than 1,which confirmed that modi-fied biochar had a good adsorption effect on Pb(Ⅱ).In conclusion,the environmentally friendly phosphoric acid modified isatidis sludge-based biochar can be used as an effective adsorbent to re-move Pb(Ⅱ)from water systems.
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维普
