Recycling aluminum from polyaluminum chloride sludge through acid dissolution and cation resin separation/purification.

Autor: Liu J; Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China., Zhang J; Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: zhangjianfeng@xauat.edu.cn., Dai Z; Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China., Li B; Xi'an Water Supply Corporation Limited, Xi'an 710082, China., Chen X; Shaanxi Key Laboratory of Environmental Engineering, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China., Meng X; Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, USA.
Jazyk: angličtina
Zdroj: Water research [Water Res] 2024 Sep 15; Vol. 262, pp. 122096. Date of Electronic Publication: 2024 Jul 15.
DOI: 10.1016/j.watres.2024.122096
Abstrakt: To recycle aluminum (Al) from waterworks sludge resulting from polyaluminum chloride (PAC) used as coagulants, this study proposed an innovative strong acidic cation (SAC) exchange resin treatment strategy for Al separation from coexisting fulvic acid (FA) and heavy metals (HMs) in the H 2 SO 4 leachate of PAC sludge. Fluorescence titration confirmed the breakdown of the Al-FA complex at pH 2.0, which facilitated Al separation from FA in the acidic leachate. The species distribution of the dissociated Al (i.e. Al a , Al b , and Al c ) significantly influenced the adsorption of Al onto the cation exchange resin. The continuous release of H + during the cation exchange reaction greatly promoted the transformation of dissociated Al c and Al b into Al a , thereby improving the adsorption of total Al. Moreover, the SAC resin column successfully separated the codissolved HMs from the Al in the leachate even at an influent pH of 2.8, which was attributed to the greater selectivity of the sulfonate groups on the cation exchange resin for free Al 3+ . The Al eluted from the exhausted resin with 1.1 M H 2 SO 4 was collected as the recycled coagulant after proper pH adjustment. The Al adsorption capacity of the SAC resin decreased by approximately 5 % with each operation cycle and was regained by complete regeneration with 1.8 M H 2 SO 4 after 5 cycles. Overall, the integrated efficiency of Al recovery from PAC sludge by H 2 SO 4 acidification and SAC resin separation/purification reached 70.10 %. The recycled Al from sludge has a water treatment performance comparable to that of fresh PAC coagulant.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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