Influences of chemically controlled Ca-bearing minerals in chitosan on Pb 2+ removal efficiency
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RESEARCH ARTICLE
Influences of chemically controlled Ca-bearing minerals in chitosan on Pb2+ removal efficiency Ohidul Alam 1 & Xiuchen Qiao 1 Received: 17 February 2020 / Accepted: 5 August 2020 # Springer Nature Switzerland AG 2020
Abstract Highly purified chitosan was generally preferred for heavy metal (HM) removal and the preparation parameters varied largely without any agreement. This study investigated to the influences of chitin with different purities on the HM removal of corresponding chitosan. Sea shrimp waste was used as raw materials and Pb2+ was used as target HM. The results of orthogonal experimental analysis showed that only acid concentration played an important role in the deproteinization and demineralization processes of the chitin preparation under HCl, H2SO4 and CH3COOH treatment. Ca-bearing minerals (CBM) but not free –NH2 group of chitosan played a major role in the removal of Pb2+ from solution. Partly purified chitosan mainly removed Pb2+ by precipitation and then biosorption. The dissociation of Ca2+ from CBM elevated pH value of Pb2+ solution which benefited to precipitation and the formation of NH2-Pb2+. Partly purified chitosan prepared from HCl and CH3COOH treated chitin showed 720–753 mg/g of Pb2+ adsorption at the initial pH value of 6.0; however, highly purified chitosan prepared from HCl treated chitin showed only 45–160 mg/g. Chitosan prepared from H2SO4 treated chitin showed 720–752 mg/g of Pb2+ adsorption. This research found the unexplored information for the industrial application of chitosan with minimum cost but the highest HM removal efficiency. Keywords Ca-bearing minerals . Deproteinization . Demineralization . Chitosan . Lead . Shrimp wastes
Introduction A large amount of heavy metals (HMs) are consumed worldwide by industries and the discarded HMs or their compounds have exacerbated serious environmental problems and received great attention in last several decades [1–3]. Many chemical, physical, biological, physico-chemical, biochemical, biophysical and thermal methods have been developed to treat HM contaminated water, soil and solid waste in order to control HM spread on the environment [4–10]. Adsorption is one of the physico-chemical methods [2, 3, 11]. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s40201-020-00521-9) contains supplementary material, which is available to authorized users. * Xiuchen Qiao [email protected] 1
State - Key Laboratory of Chemical Engineering, State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, People’s Republic of China
Adsorption is a widely used technology for HM removal from contaminated wastewater. Different types of low-cost and locally available materials that have high metal-binding capacity are used for HM adsorption [8, 12, 13]. Chitosan is an effective scavenger for HM ions [14, 15]. It is p
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