title: Adsorption of cadmium by biochar derived from municipal sewage sludge: Impact factors and adsorption mechanism.
abstract: Static equilibrium experiments were carried out to investigate the impact factors and the mechanism of cadmium adsorption on biochar derived from municipal sewage sludge. An appropriate dosage of biochar is sufficient; in the experiment, 0.2% is the optimal dosage for the largest removal capacity, while the removal capacity of biochar reduces with the increasing dosage. pH is another dominant factor of the adsorption process. The removal capacity of biochar is lower than 20 mg·g(-1) when the solution initial pH is lower than 2 pH units, comparatively retaining more than 40 mg·g(-1) at the solution initial pH higher than 3 pH units. Temperature has weak influence on the adsorptive performance. The main mechanism of the adsorption process of biochar for cadmium mainly involves (1) surface precipitation by forming insoluble cadmium compounds in alkaline condition, and (2) ion exchange for cadmium with exchangeable cations in the biochar, such as calcium ions.
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Tan
authors.initials: T
authors.lastname: Chen
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Zeyu
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: School of Environmental Science and Engineering, Chang'an University, Xi'an 710064, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Han
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Ruihong
authors.initials: R
authors.lastname: Meng
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: htwang@tsinghua.edu.cn.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: luwenjing@tsinghua.edu.cn.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Lu
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D002606:Charcoal / Q000378:metabolism*; D007477:Ions; D009111:Local Government; D012722:Sewage / Q000737:chemistry*; D012996:Solutions; D013696:Temperature
chemical_list: D007477:Ions; D012722:Sewage; D012996:Solutions; C540010:biochar; D002104:Cadmium; D002606:Charcoal
keywords: Adsorption; Biochar; Heavy metal; Impact factor; Mechanism