Abstract

The cyanide-containing effluents originate from, e.g., mining, coking, electroplating and chemical syntheses. The form and concentration of cyanide, and the effluent matrix depend on the effluent source. Electroplating effluents contain extreme amounts of free cyanide (fCN), e.g., >50 g/L, along with metal cyanide complexes. “Raw coking effluents”, i.e. coke oven effluents after tar and ammonia separation, contain up to over 100 mg total cyanide (TCN)/L, a significant part of which is fCN. They are also contaminated with phenols, other organic compounds, and inorganic salts. They are generated in extreme quantities such as 120–150 m³/h in a plant with annual coke production of 4.2 Mt. Adequate remediation of these effluents is a challenging task, and requires specific methods for each effluent. Conventional physicochemical, chemical, and biological solutions are usually far from optimal in terms of effectiveness, environmental impact or cost. This has led to intensive research in the field of elimination of cyanide from wastewaters. This work will provide a review of recent advances in this research area. In contrast to most previous reviews, this work offers a general overview of innovative methods of different types (oxidation, flocculation, adsorption, electro(dia)lysis, photocatalysis, bioassimilation, biocatalysis). The processes are characterized in terms of their suitability for different effluents, as well as their efficiency, scalability, and cost, where data are available. The study attempts to highlight the most promising solutions. These are likely to include principally the combinations of different (physico)chemical and biological approaches able to eliminate various forms of cyanide along with other contaminants.

摘要

含氰化物流出物源自例如采矿、焦化、电镀和化学合成。氰化物的形式和浓度以及流出物基质取决于流出物的来源。电镀废水含有大量的游离氰化物 (fCN)，例如 >50 g/L，以及金属氰化物络合物。“原焦化流出物”，即焦油和氨分离后的焦炉流出物，含有高达 100 毫克以上的总氰化物 (TCN)/L，其中很大一部分是 fCN。它们还被苯酚、其他有机化合物和无机盐污染。它们的产生量非常大，例如 120–150 m ³/h 在年焦炭产量为 4.2 公吨的工厂中。对这些流出物进行充分修复是一项具有挑战性的任务，并且需要针对每种流出物使用特定的方法。就有效性、环境影响或成本而言，传统的物理化学、化学和生物解决方案通常远非最佳。这导致了在消除废水中氰化物领域的深入研究。这项工作将回顾这一研究领域的最新进展。与之前的大多数评论相比，这项工作对不同类型的创新方法（氧化、絮凝、吸附、电（渗析）、光催化、生物同化、生物催化）进行了总体概述。这些工艺的特点在于它们对不同流出物的适用性，以及它们的效率、可扩展性和成本，数据可用的地方。该研究试图强调最有希望的解决方案。这些可能主要包括能够消除各种形式的氰化物以及其他污染物的不同（物理）化学和生物方法的组合。