芬顿污泥制备磁性生物炭回用于对硝基苯酚的去除及机制

芬顿/絮凝组合工艺在处理难降解有机物废水时会产生大量的芬顿污泥，会提高废水处理成本，同时也会对环境构成威胁，迫切需要开发一种绿色可持续的方法实现芬顿污泥资源化利用.该研究通过将处理PNP(对硝基苯酚)废水产生的芬顿污泥和污水厂生化污泥共热解，原位制备具有高催化活性的MBC(磁性生物炭)，并作为多相芬顿催化剂用于去除PNP，实现“以废治废”.结果表明：当芬顿污泥和生化污泥质量比为1∶1、热解温度为800℃时，制备得到的MBC-800-3催化性能最佳；合适的混合比例可有效避免颗粒聚集，高温形成缺陷结构和多种铁相，为MBC-800-3提供了丰富的反应活性位点；当废水初始pH为3、H₂O₂浓度为60 mmol/L、MBC-800-3投加量为0.4 g/L时，PNP和TOC(总有机碳)的去除率均最高，在催化反应100 min时分别达到98%和62%；酸性条件下，MBC活化H₂O₂产生·OH和·O₂-催化降解废水的有机物，其中，·OH作为主要活性物种，其来源包括均相芬顿反应和非均芬顿相反应...

Removal and Mechanism of p-Nitrophenol by Magnetic Biochar Prepared from Fenton Sludge

When the combined Fenton/flocculation process is used to treat refractory organic wastewater, a large amount of Fenton sludge is generated, which increases the cost of wastewater treatment and poses a threat to the environment. It is urgent to develop a green and sustainable method to achieve resource utilization of Fenton sludge. The disposal of Fenton sludge often leads to secondary pollution. Sludge pyrolysis appears to be less polluting than traditional methods and has received increasing attention from domestic and foreign scholars. In this study, magnetic biochar (MBC) with high catalytic activity was prepared in situ by co-pyrolysis of Fenton sludge produced by the treatment of p-nitrophenol (PNP) wastewater and biochemical sludge from a sewage plant, and a heterogeneous Fenton catalyst was used to remove PNP in what can be considered as ‘treating waste with waste’. The results showed that the best performing catalytic (named MBC-800-3) was obtained when the mass ratio of Fenton sludge to biochemical sludge was 1∶1 and the pyrolysis temperature was 800 ℃. This mixing ratio effectively avoided particle aggregation, while high temperature formed defective structures and various iron phases, that provided abundant reactive sites on MBC-800-3. When the initial pH of the wastewater was 3, the H₂O₂ concentration was 60 mmol/L and the MBC-800-3 dosing was 0.4 g/L, the removal efficiencies of PNP and total organic carbon were the highest at 100 min of catalytic reaction, reaching 98% and 62%, respectively. Under acidic conditions, MBC activated H₂O₂ to produce ·OH and ·O₂? that catalyzed the degradation of organic matter in wastewater. Among them, ·OH was the main active species, and the sources included both homogeneous and heterogeneous Fenton reactions. The study shows that MBC-800-3 has high catalytic activity as well as good stability and regeneration, thereby exhibiting good application potential, which is of significance for the resource utilization of Fenton sludge.