nZVI@BC活化PMS氧化高硫酸盐废水中亚甲基蓝的研究

Biochar Supported Nanoscale Zero-Valent Iron Used As an Efficient Peroxymonosulfate Activator to Accelerate Methylene Blue Degradation in High-SulfateWastewater

采用由小麦秸秆制备的生物炭(Biochar,BC)作为纳米零价铁(Nanoscale zero-valent iron,nZVI)载体,制备出一种高效非均相催化剂-生物炭负载纳米零价铁(nZVI@BC),用于活化过一硫酸盐(Peroxymonosulfate,PMS)降解高硫酸盐印染废水中的典型染料亚甲基蓝(Methylene Blue,MB)。nZVI@BC表征结果表明,BC具有优良的稳定性且富含活性官能团,负载于BC上的nZVI分散性好。通过批次实验探究了初始pH、nZVI@BC投加量、PMS浓度和硫酸钠浓度对nZVI@BC/PMS体系降解MB的影响。结果表明,在MB初始质量浓度为40 mg/L,pH为3,nZVI@BC投加量为0.2 g/L,PMS质量浓度为0.4 g/L,Na_(2)SO_(4)浓度为0.2 mol/L的条件下,反应30 min后nZVI@BC/PMS体系对MB的降解率达到90.36%。Na_(2)SO_(4)浓度超过0.3 mol/L后,表现出对MB降解过程的抑制效果。自由基猝灭实验结果表明,硫酸根自由基和羟基自由基均参与反应且硫酸根自由基发挥主要作用。

Using biochar(BC)prepared from wheat straw as the carrier of nanoscale zero-valent iron(nZVI),a highly efficient heterogeneous catalyst nZVI@BC was prepared,which was used to activate peroxymonosulfate(PMS)for the degradation of Methylene Blue(MB),the typical contaminant of high-sulfate printing and dyeing wastewater.The characterization results of nZVI@BC indicated that BC had excellent stability and was rich in active functional groups,and the nZVI supported on BC had good dispersibility.The effects of initial pH,nZVI@BC dosage,PMS concentration and Na_(2)SO_(4)concentration on the degradation of MB were comprehensively investigated by the batch experiments.The results suggested that the MB removal rate could reach 90.36%after 30 min,under the following condition:40 mg/L of MB initial concentration,pH=3,0.2 g/L of nZVI@BC dosage,0.4 g/L of PMS concentration and 0.2 mol/L of Na_(2)SO_(4)concentration.When Na_(2)SO_(4)concentration exceeded 0.3 mol/L,it exhibited an inhibitory effect on the MB degradation process.The results of radical quenching experiments showed that both sulfate radical and hydroxyl radicals participated in the MB degradation process and sulfate radical played a major role.