title: Equilibrium, Kinetic, and Thermodynamic Studies on the Adsorption of Cadmium from Aqueous Solution by Modified Biomass Ash.
abstract: Natural biomass ash of agricultural residuals was collected from a power plant and modified with hexagonal mesoporous silica and functionalized with 3-aminopropyltriethoxysilane. The physicochemical and morphological properties of the biomass ash were analyzed by ICP-OES, SEM, TEM-EDS, FTIR, and BET analysis. The adsorption behavior of the modified product for Cd2+in aqueous solution was studied as a function of pH, initial metal concentration, equilibrium time, and temperature. Results showed that the specific surface area of the modified product was 9 times that of the natural biomass ash. The modified biomass ash exhibited high affinity for Cd2+and its adsorption capacity increased sharply with increasing pH from 4.0 to 6.0. The maximum adsorption capacity was 23.95 mg/g in a pH 5 solution with an initial metal concentration of 50 mg/L and a contact time of 90 min. The adsorption of Cd2+onto the modified biomass ash was well fitted to the Langmuir model and it followed pseudo-second-order kinetics. Thermodynamic analysis results showed that the adsorption of Cd2+was spontaneous and endothermic in nature. The results suggest that the modified biomass ash is promising for use as an inexpensive and effective adsorbent for Cd2+removal from aqueous solution.
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Science, Nanjing 210008, China; National Engineering and Technology Research Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Liujiazhan Plantation, Yingtan 335211, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lei
authors.identifier: 0000-0001-5731-1502
authors.initials: L
authors.lastname: Xu
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Science, Nanjing 210008, China; National Engineering and Technology Research Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Liujiazhan Plantation, Yingtan 335211, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xuebo
authors.initials: X
authors.lastname: Zheng
authors.affiliation: School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China.
authors.forename: Hongbiao
authors.initials: H
authors.lastname: Cui
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Science, Nanjing 210008, China; National Engineering and Technology Research Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Liujiazhan Plantation, Yingtan 335211, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhenqiu
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Science, Nanjing 210008, China; National Engineering and Technology Research Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Liujiazhan Plantation, Yingtan 335211, China.
authors.forename: Jiani
authors.initials: J
authors.lastname: Liang
authors.affiliation: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Key Laboratory of Soil Environment and Pollution Remediation, Chinese Academy of Science, Nanjing 210008, China; National Engineering and Technology Research Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Liujiazhan Plantation, Yingtan 335211, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jing
authors.identifier: 0000-0002-3426-1300
authors.initials: J
authors.lastname: Zhou