Utilization of electrolytic manganese residue and bauxite to synthesize zeolite a for pickle liquor adsorption: Characterization, mechanisms and performance

Abstract

Electrolytic manganese residue (EMR) and its pickle liquor are extremely hazardous wastes that can cause significant environmental and biological hazards. In order to solve these problems, this paper used EMR and bauxite (BA) as the main raw materials to synthesize zeolite A (EMRZ), and carried out adsorption and purification of pickle liquor so as to realize the comprehensive utilization of EMR and BA. The study investigated the optimal parameters for the synthesis of zeolite and subsequently characterized the synthesized EMRZ. The characterization results revealed that the synthesized EMRZ exhibited notable attributes such as high purity, high crystallinity, and exceptional ion exchange capabilities. Subsequently, the synthesis mechanism of EMRZ was elucidated using XRD, FTIR, Raman spectroscopy, and MAS NMR techniques. The growth process of EMRZ involved three distinct stages, namely the growth induction period, rapid growth phase, and growth completion stage. More specifically, the transformation sequence was observed as follows: double four-membered rings (D4R) → β cages → α cages → zeolite A crystals. Besides, the migration and transformation of Si and Al in EMR were explored, and the mechanism was further expounded. In addition, the synthesis of EMRZ has been evaluated economically and compared with other zeolites synthesized by different methods. It was discovered that EMRZ has a higher economic value. Moreover, an investigation was conducted on the adsorption effect of EMRZ on impurity ions present in pickle liquor. It was discovered to be effective at removing impurity ions, suggesting that EMRZ is a feasible purification material for pickle liquor. Furthermore, the adsorption mechanism was ion exchange between impurity ions and Na ions, and EMRZ was successfully regenerated. The findings of the study validate the potential of EMRZ as a highly effective adsorbent for the treatment of pickle liquor, thereby offering a viable approach for the comprehensive utilization of EMR.