镁铝层状双氢氧化物在沉淀过程中增强了酸性矿山废水的硫酸盐去除及澄清效果。

Mg/Al LDH Enhances Sulfate removal and Clarification of AMD Wastewater in Precipitation Processes.

作者信息

Maziarz Paulina, Matusik Jakub, Leiviskä Tiina

机构信息

Department of Mineralogy, Petrography and Geochemistry; Faculty of Geology, Geophysics and Environmental, Protection; AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow, Poland.

Chemical Process Engineering, University of Oulu, P.O. Box 4300, FIN-90014 Oulu, Finland.

出版信息

Materials (Basel). 2019 Jul 23;12(14):2334. doi: 10.3390/ma12142334.

DOI:10.3390/ma12142334

PMID:31340458

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC6679161/

Abstract

The sulfate removal from acid mine drainage (AMD) water (initial concentration: 5301 mg/L) was investigated by precipitation and/or adsorption using calcium hydroxide (Ca(OH)) and synthetic layered double hydroxide (LDH) of the Mg/Al type. The exclusive use of LDH efficiently removed sulfates (64.2% reduction); however, alteration of its structure was observed due to low pH. The use of Ca(OH) in different doses calculated in relation to gypsum stoichiometry allowed to achieve an 86% removal of sulfates. Depending on the equilibrium pH, gypsum or ettringite were the main identified phases. The two-step removal, involving the use of Ca(OH) followed by LDH, was less efficient than the use of the Ca(OH)/LDH mixture when the stoichiometric amount of Ca(OH) in relation to gypsum was applied. The application of mixture resulted in a fast pH increase, which prevented destruction of the LDH structure. Most importantly, the use of mixture significantly reduced the sludge volume and enhanced its settling velocity.

摘要

采用氢氧化钙（Ca(OH)）和镁铝型合成层状双氢氧化物（LDH），通过沉淀和/或吸附法研究了从酸性矿山排水（AMD）水中去除硫酸盐（初始浓度：5301 mg/L）的情况。单独使用LDH能有效去除硫酸盐（减少64.2%）；然而，由于pH值较低，观察到其结构发生了变化。按照石膏化学计量比计算使用不同剂量的Ca(OH)，可实现86%的硫酸盐去除率。根据平衡pH值，石膏或钙矾石是主要识别出的物相。当使用与石膏化学计量比的Ca(OH)时，两步去除法（先使用Ca(OH)，再使用LDH）的效率低于使用Ca(OH)/LDH混合物的效率。混合物的应用导致pH值快速升高，从而防止了LDH结构的破坏。最重要的是，混合物的使用显著减少了污泥体积并提高了其沉降速度。