DataSheet1_Sustainable Chromium Encapsulation: Alkali Activation Route.PDF

This article highlights recent experimental advances in the use of inorganic substances in the encapsulation of pollutants and, in particular, discusses the potential applicability and constraints of the geopolymerization process for the treatment of wastewater containing chromium. A great percentage of waste containing chromium salts is produced by the leather industry during the tannery process. Such industrial waste is in the form of liquor containing almost 40% of the initial chromium combined with many other pollutants. The stabilization/solidification (S/S) treatment of this type of waste must be combined with chromium encapsulation in an economic, environmentally friendly and efficient process to be industrially feasible. Here we present a novel process in which the wastewater is used as a component of the formulation together with a clay by-product and with the addition of NaOH pellets with the goal of a no-water plus no-waste technology approach. The final solidified “ceramic-like” material successfully immobilized the heavy metal cations as well as anions and macromolecules of surfactants, avoiding environmental damages to soil and groundwater. The article is completed by mentioning other S/S processes where wastewater has been treated and the resulting sludge encapsulated. The future of the S/S technologies in the tannery industry should progress in the direction of significantly reducing the amount of wastewater directed to the treatment plants, with associated reductions in transport and their CO2 emissions. This article intends to be a contribution in the direction of preventing waste, aligning circular economy and waste management objectives.

本文综述了无机材料用于污染物封装固定领域的最新实验进展，并重点探讨了地质聚合工艺（geopolymerization）在含铬废水处理中的应用潜力与局限。制革工业在鞣制过程中会产生大量含铬盐废弃物，此类工业废弃物以废液形式存在，其中初始铬的占比近40%，且混杂多种其他污染物。针对该类废弃物的稳定化/固化（S/S）处理，需结合铬的封装固定技术，采用经济环保且高效的工艺路径，方可满足工业应用的可行性要求。本文提出一种新型工艺：将含铬废水作为组分之一，与黏土副产物混合，并添加氢氧化钠（NaOH）颗粒，旨在实现"零水+零废物"的技术路径。最终得到的类陶瓷固化材料可成功固定重金属阳离子、阴离子及表面活性剂大分子，避免对土壤与地下水造成环境破坏。本文还提及了其他已应用于废水处理并对所产污泥进行封装固定的S/S工艺。未来制革工业的S/S技术发展方向应为大幅减少送往处理厂的废水量，从而降低运输成本与二氧化碳排放量。本文旨在为推动废弃物预防、契合循环经济与废弃物管理目标贡献思路。