Abstract:In order to alleviate the pressure of solid waste treatment and develop cheap and efficient Pb2+ adsorbent products, spent Pleurotus ostreatus substrate (PS) was used as raw material to prepare biochar (PSBC) by limited oxygen pyrolysis at temperature of 250, 450 and 650 ℃, and the surface physical and chemical properties of the samples were studied by BET, SEM-EDS, XRD and FT-IR. The characteristics and mechanism of Pb2+ adsorption on PSBC were studied by the experiments of batch adsorption, mechanism qualitative and quantitative analysis. The results showed that the specific surface area and aromatization of PSBC increased sharply and oxygen-containing functional groups decreased when the pyrolysis temperature increased from 250 ℃ to 650 ℃. The adsorption of Pb2+ on PSBC was pH-dependent, and the maximum adsorption amount occurred at pH 6.0. The pseudo second order kinetic model and the Freundlich model were suitable for fitting the adsorption process of Pb2+ onto PSBC, which proved that the process was chemical adsorption occurring on the multi-molecular layer. Compared with PS250 and PS450, PS650 had larger specific surface area, better-developed mesoporous structure and more binding sites for Pb2+ adsorption. The maximum adsorption capacity calculated by Langmuir model was 215.30 mg?g?1, which was even higher than those of some modified biochars. The results of qualitative and quantitative analysis showed that the precipitation of carbonate always dominated the adsorption process of Pb2+ on PSBC, being accompanied by the complexation of oxygen-containing functional groups and the interaction between π-Pb2+.The results can provide reference for solid waste management of spent mushroom substrate and the removal of Pb2+ from sewage. Key words:spent Pleurotus ostreatus substrate/ biochar/ lead pollution/ pyrolysis temperature/ adsorption characteristics and mechanism.
图1PSBC吸附前后的电镜能谱图(放大4 000倍) Figure1.SEM-EDS images of PSBC before and after adsorption(×4 000 times)
图8不同吸附机制对PSBC吸附Pb2+的贡献吸附量与贡献率 Figure8.Estimated contribution of Pb2+ sorption on PSBC, and the contribution percentage of different mechanisms to the overall Pb2+ sorption on PSBC
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1.College of Urban and Rural Construction, Shanxi Agricultural University, Taigu 030801, China 2.College of Resources and Environment, Shanxi Agricultural University, Taigu 030801, China Received Date: 2020-01-06 Accepted Date: 2020-04-21 Available Online: 2020-11-11 Keywords:spent Pleurotus ostreatus substrate/ biochar/ lead pollution/ pyrolysis temperature/ adsorption characteristics and mechanism Abstract:In order to alleviate the pressure of solid waste treatment and develop cheap and efficient Pb2+ adsorbent products, spent Pleurotus ostreatus substrate (PS) was used as raw material to prepare biochar (PSBC) by limited oxygen pyrolysis at temperature of 250, 450 and 650 ℃, and the surface physical and chemical properties of the samples were studied by BET, SEM-EDS, XRD and FT-IR. The characteristics and mechanism of Pb2+ adsorption on PSBC were studied by the experiments of batch adsorption, mechanism qualitative and quantitative analysis. The results showed that the specific surface area and aromatization of PSBC increased sharply and oxygen-containing functional groups decreased when the pyrolysis temperature increased from 250 ℃ to 650 ℃. The adsorption of Pb2+ on PSBC was pH-dependent, and the maximum adsorption amount occurred at pH 6.0. The pseudo second order kinetic model and the Freundlich model were suitable for fitting the adsorption process of Pb2+ onto PSBC, which proved that the process was chemical adsorption occurring on the multi-molecular layer. Compared with PS250 and PS450, PS650 had larger specific surface area, better-developed mesoporous structure and more binding sites for Pb2+ adsorption. The maximum adsorption capacity calculated by Langmuir model was 215.30 mg?g?1, which was even higher than those of some modified biochars. The results of qualitative and quantitative analysis showed that the precipitation of carbonate always dominated the adsorption process of Pb2+ on PSBC, being accompanied by the complexation of oxygen-containing functional groups and the interaction between π-Pb2+.The results can provide reference for solid waste management of spent mushroom substrate and the removal of Pb2+ from sewage.