有色金属(冶炼部分)

砷中毒会显著降低选择性催化还原（Selective Catalytic Reduction, SCR）脱硝催化剂的活性，限制其重复利用，亟需绿色高效的再生技术。提出一种基于生物酸浸渍的脱砷再生工艺，旨在实现砷的高效去除及催化剂活性的恢复。采用扫描电镜-能谱、X射线荧光光谱和电感耦合等离子体发射光谱等手段，对失活催化剂的元素分布及组成进行系统分析，并对比评估四种脱砷体系。结果表明，生物酸体系在砷去除效率表现最优。通过单因素优化确定其最佳工艺参数为：温度50℃、固液比5%、初始pH 0.6、处理时间8 h，采用单倍浓缩生物酸溶液处理，在该条件下，砷脱除率达81.63%，残余含量低于200 g/t。经再生处理后，再生催化剂的NO转化效率恢复至100%。该方法绿色环保、操作简便，展现出良好的工业应用前景。

Selective catalytic reduction(SCR) catalysts are widely used for industrial flue gas denitrification, but are prone to deactivation due to arsenic contamination from fuel sources. Traditional arsenic removal methods are associated with high costs and environmental risks, underscoring the urgent need for a green and efficient regeneration technology. This study proposes a green regeneration process for arsenic removal from SCR catalysts based on microbial acid production. The process utilizes biologically produced acids from the sulfuroxidizing acidophilic bacterium Acidithiobacillus thiooxidans to efficiently remove adsorbed and deposited arsenic contaminants via wet impregnation. Inorganic acids generated during microbial metabolism significantly lower the pH value of system, enhancing proton attack capacity and facilitating the dissolution of arsenic oxides. Moreover, the bioleaching system is enriched with thiol-containing(— SH) amino acid-derived small molecules, which exhibit strong nucleophilicity under acidic conditions. These molecules effectively disrupt As— O bonds and promote the conversion of arsenic oxides into soluble arsenates, thereby achieving efficient arsenic removal. Characterization of the deactivated catalysts using scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS), X-ray fluorescence(XRF), and inductively coupled plasma optical emission spectrometry(ICP-OES) reveals that arsenic is primarily distributed as localized deposits on the catalyst surface and within its pores. In addition, the contents of active components such as vanadium(V) and tungsten(W) are significantly reduced. To evaluate the arsenic removal performance, four representative arsenic removal system were compared: inorganic acid leaching, organic chelating agent-assisted treatment, alkaline washing, and the bio-acid system. The results show that the bio-acid system outperforms the others in both arsenic removal efficiency and preservation of active components. On this basis, single-factor experiments were conducted to optimize the arsenic removal parameters, including the addition of vitamin C, humic acid, and concentrated bio-acid to enhance leaching efficiency. The optimal treatment conditions are determined as follows: using singly concentrated bio-acid solution under conditions of temperature of 50 ℃, solid-to-liquid ratio of 5%, initial pH value of 0.6, and treatment time of 8 hours. Under these conditions, the arsenic removal rate is 81.63%, and the residual arsenic content in the catalyst is reduced to below 200 g/t, meeting the reuse standard. Subsequently, vanadium and tungsten active components were replenished via an impregnationcalcination method, and the regenerated catalyst was tested in a fixed-bed reactor for NO reduction performance. The results indicate that a significant recovery of NO conversion efficiency at low-to-moderate temperatures, with a 100% conversion rate achieved at 300 ℃. This confirms that the process not only effectively eliminates arsenic poisoning but also fully restores the catalyst's denitrification activity. This study establishes a green bio-acid-based arsenic removal and regeneration system centered on Acidithiobacillus thiooxidans, enabling the efficient and environmentally friendly regeneration of deactivated SCR catalysts.