Degradation of n-butyl xanthate using fly ash as heterogeneous Fenton-like catalyst

Heterogeneous Fenton-like process using fly ash as a catalyst was studied to degrade n-butyl xanthate form aqueous solution. The different reaction parameters on the degradation efficiency of the process were investigated. The fly ash/H2O2 catalyst possesses a high oxidation activity for n-butyl xanthate degradation in aqueous solution. It is found that both the dosage of catalyst and initial solution pH significantly affect the n-butyl xanthate conversion efficient. The results indicate that by using 1.176 mmol/L H2O2 and 1.0 g/L fly ash catalyst with mass fraction of 4.14% Fe（III） oxide at pH 3.0, almost 96.90% n-butyl xanthate conversion and over 96.66% COD removal can be achieved within 120 min with heterogeneous catalysis by fly ash. CS2 as an intermediate of n-butyl xanthate oxidation. Finally, it is demonstrated that the fly ash/H2O2 catalytic oxidation process can be an efficient method for the treatment of n-butyl xanthate containing wastewater.     

类Fenton试剂及其在废水处理中的应用

概述了H2O2＋UV、H2O2＋Fe2^＋ ＋UV（UV／Fenton）、H2O2＋Fe2^＋ ＋O2、H2O2＋UV＋O2、H2O2＋Fe2^＋ ＋uV＋O2、Fe3^＋ ＋H2O2及电Fenton等几种类Fenton试剂，并对其在废水处理中的应用作了较为详细的阐述。     

Fe3O4 @ SPC类芬顿氧化降解苯酚

以钙基蒙脱石（Ca-MMT）为原料，采用一步层间模板法制备了四氧化三铁@硅柱撑蒙脱石催化材料（Fe3O4@SPC），通过XRD、FTIR、BET、SEM对材料的形貌、结构进行表征显示，Fe3O4@SPC具有d001=3.30 nm的晶面间距和4.47 nm的介孔，Fe3O4颗粒主要分散在SPC的外表面。以苯酚为降解目标污染物，考察了Fe3O4@SPC的催化活性和稳定性。结果表明，当苯酚质量浓度为100 mg/L，pH值为2.5，催化剂质量浓度为0.5 g/L，H2O2投加量为0.2 mL，反应时间为120 min时，苯酚的去除率为100％；催化剂经过5次循环使用后，苯酚的降解率依然保持在90%以上。通过GC-MS分析苯酚降解生成的中间体，结合叔丁醇淬灭实验，发现?OH氧化在非均相类芬顿催化氧化降解苯酚体系中起主导作用，推测了苯酚可能的降解路径。     

Phenol oxidation kinetics in water solution using iron(3)-oxide-based nano-catalysts

The influence of inorganic ions (HCO(3), PO(4)/HPO(4)/H(2)PO(4), Cl, SO(4), Ca, Na and Mg) on the advanced chemical oxidation process of organic compounds dissolved in water is reported here. The catalytic behavior of iron(3)-oxide-based nano-particles was investigated together with inorganic ions and hydrogen peroxide concentrations, and pH level. Phenol was chosen as a typical organic contaminant for this study as a simulating pollutant. The limiting concentrations of radical scavengers making the oxidation process inefficient were identified. The strong effect of concentration of radical scavengers HCO(3), PO(4)/HPO(4)/H(2)PO(4), the nano-catalyst and hydrogen peroxide concentrations, and pH on the phenol oxidation rate and lag time period before reaction starts was determined. It was shown that Cl, SO(4), Ca, Na and Mg ions had no significant effect on the kinetics of phenol oxidation.     

赤泥基非均相催化剂类Fenton催化降解金橙Ⅱ

采用糖蜜酒精废液协同H2SO4对赤泥进行酸化改性,再经高温焙烧处理,得到赤泥基非均相催化剂（SMA-CA/赤泥）,通过XRD、EDS、N2吸附脱附技术对SMA-CA/赤泥进行了表征,并将其用于金橙Ⅱ的类Fenton催化降解。表征结果显示：经酸化和焙烧,赤泥中的α-FeOOH转变为SMA-CA/赤泥中的α-Fe2O3,且酸化改性使得SMA-CA/赤泥碱含量显著降低;与未添加糖蜜酒精废液酸化改性的赤泥基非均相催化剂相比, SMA-CA/赤泥的孔径增大,大孔分布提高。实验结果表明：在初始溶液pH值为3、H2O2投加量50 mmol/L、金橙Ⅱ质量浓度40 mg/L、反应时间6 h的条件下,金橙Ⅱ去除率达到86.79%;该催化降解过程符合一级动力学模型。     

TiO2/MIL-88B(Fe)/聚丙烯复合熔喷非织造材料的制备及其性能

为使聚丙烯(PP)熔喷非织造材料功能化,扩大其在水处理方面的应用,以2,4-对苯二甲酸、六水合三氯化铁、纳米氧化钛为原料,PP熔喷非织造材料为基材,首先通过浸渍工艺预处理基底材料,再通过溶剂热法在PP熔喷非织造材料基材上负载金属有机框架材料TiO₂/MIL-88B(Fe),制备了TiO₂/MIL-88B(Fe)/PP复合熔喷非织造材料。借助红外光谱、X射线衍射及孔径分析对TiO₂/MIL-88B(Fe)/PP复合熔喷非织造材料的结构与性能进行了表征。结果表明TiO₂/MIL-88B(Fe)成功负载在PP熔喷非织造材料表面。在可见光照射条件下,TiO₂/MIL-88B(Fe)/PP复合熔喷非织造材料对甲基蓝、酸性橙7及酸性红73这3种染料的降解率均达到80%以上,其中对甲基蓝的降解率可达86%,对较难降解的罗丹明B的降解率也达到了59%。在重复使用5次后,复合熔喷非织造材料对甲基蓝降解率均在70%以上,性能较稳定。     

Mg-Al CLDHs/H2O2体系降解结晶紫染料废水的研究

以Mg-Al CLDHs (Calcined Mg-Al layered double hydroxide)和H2O2组成的类芬顿体系催化降解结晶紫(Crystal violet,CV)染料废水.考察了pH值、催化剂用量、氧化剂用量、染料起始浓度、反应温度、反应时间等因素的影响,并对Mg-Al CLDHs催化剂的再生能力进行了测试.结果表明:对浓度为40 mg/L的结晶紫溶液,当Mg-AlCLDHs用量为0.005 g,H2O2用量为1 mL,pH为7.0,降解温度为35℃,反应时间为15 min,结晶紫脱色率98％以上,催化剂再生性良好.动力学研究表明该反应符合一级动力学模型,35℃时速率常数为0.28 min-1,表观活化能为46.03 kJ·mol-1.     

活性艳蓝经多相类芬顿预处理前后对厌氧污泥性能的影响

以蒽醌类染料活性艳蓝为目标污染物,探讨了其对产甲烷菌的抑制机理;分析了其经多相类芬顿预处理前后对厌氧污泥EPS、粒径分布、金属离子含量的影响;同时对活性艳蓝的降解途径进行了探究。结果表明,活性艳蓝对产甲烷菌具有代谢毒性甚至生理性毒性;其进入厌氧反应器后,会造成COD去除率降低;颗粒污泥粒径减少,污泥中钙、镁离子浓度分别由40.5和16.2 mg·L^-1降低到22.5和6.8 mg·L^-1,污泥的稳定性与絮凝性变差。而经多相类芬顿预处理后,COD去除率可达90%以上,厌氧颗粒污泥EPS总量、蛋白质含量、多糖含量分别增大到98.7、69.9和28.8 mg·(g VSS)^-1,为保持颗粒污泥的活性与稳定性提供了保障。多相类芬顿体系所产生的羟基自由基首先攻击活性艳蓝的三嗪基团及不饱和共轭键的蒽醌结构,继而生成邻苯二甲酸、苯甲酸,再被降解为丁酸、草酸、乙酸等小分子羧酸,从而降低了其毒性,有利于后续厌氧生物处理的进行。     

Catalytic degradation of phenol in sonolysis by coal ash and H2O2/O3

This study demonstrated that coal ash, as widely distributed solid waste disposal, would function as a media for organic pollutants removal in the presence or absence of H₂O₂/O₃ under ultrasonic radiation. Coal ash could act as a catalyst to generate OH radicals with the presence of H₂O₂/O₃ and consequently enhance the phenol degradation. Experimental results showed that when using coal ash as a catalyst under ultrasonic irradiation, 83.4% and 88.8% of phenol was degraded in the presence of H₂O₂ or O₃, respectively. The degradation rate of phenol would increase with increasing amount of O₃, while there was an optimal concentration of H₂O₂ (1.5 mM) for phenol degradation. Higher dosage of coal ash could result in higher phenol degradation rates. H₂O₂/coal ash/ultrasonic system could achieve better performance for phenol degradation under more acidic conditions, while more alkaline condition in O₃/coal ash/ultrasonic system favored phenol degradation. This study provides a new approach for wastewater treatment especially when contaminated with phenolic pollutants.     

微波诱导粉煤灰-H2O2处理垃圾渗滤液的研究

Fenton和类Fenton试剂广泛用于持久性有机污染物的矿化处理。微波辐射能提高Fenton和类Fen-ton法处理难降解有机废水的效率和处理能力。实验采用粉煤灰吸附分离与微波高级氧化的组合工艺处理垃圾渗滤液,以降低垃圾渗滤液的化学需氧量(COD)浓度。粉煤灰作为有机废水的吸附剂,同时粉煤灰中溶出的铁及其他过渡金属离子能与H2O2形成Fenton类试剂,产生氧化能力极强的羟基自由基(.OH),氧化处理其中的有机物。当粉煤灰量为20 g/L,pH=2,搅拌1 h后过滤分离;每1 L滤液加入2 mL 30%(质量比)的H2O2,入微波炉,设定温度80℃,功率600 W,在微波中作用20 min时,COD的去除率可达69.81%。