微波强化催化H2O2处理印染生化出水及有机物去除
Degradation of biochemical treated effluent of dyeing wastewater and its organics removal by microwave-enhanced catalytic H2O2
收稿日期: 2019-06-18
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Received: 2019-06-18
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作者简介 About authors
章波(1984-),博士,工程师电话:15895875397,E-mail:
采用微波强化催化H2O2的组合工艺处理印染废水生化处理出水,考察微波功率、温度、H2O2投加量及pH对反应效果的影响。最佳反应条件:微波输出功率为500 W、温度60 ℃、H2O2浓度为0.095 mol/L、水力停留时间18 min,此时COD去除率为79.89%。此外,在最佳反应条件下,采用XAD-8/XAD-4树脂联用技术分析进出水中疏水酸、非酸疏水物质、弱疏水物质及亲水物质的去除情况,结果表明,微波强化催化H2O2能有效去除这4类物质。
关键词:
The biochemical treated effluent of dyeing wastewater is degraded by microwave enhanced catalytic H2O2 combined process, and the influences of microwave power, temperature, H2O2 dosage and initial pH on the reaction are investigated. The optimal reaction conditions are as follows:microwave output power of 500 W, temperature of 60℃, H2O2 concentration of 0.095 mol/L and hydraulic retention time of 18 min, the COD removal rate could reach 79.89%. In addition, under the optimal reaction conditions, the removal of hydrophobic acid, non-acid hydrophobic substance, weak hydrophobic substance and hydrophilic substance in the influent and effluent is analyzed by XAD-8/XAD-4 resin combination technology. The results show that microwave-enhanced catalytic H2O2 could effectively remove these four kinds of substances.
Keywords:
本文引用格式
章波, 姚立荣, 程寒飞, 仲鑫.
Zhang Bo.
1 实验部分
1.1 水质及来源
实验所用印染废水生化出水取自江苏某工业废水处理厂,其COD为80~100 mg/L,pH为6.5~8.5,ADMI7.6为200~220。
1.2 负载型催化剂制备
催化剂采用浸渍法制备,其中Cu(NO3)2和Ni(NO3)2混合液浓度为1.5 mol/L,n(Cu):n(Ni)为4:1,载体为γ-Al2O3,浸渍时间为24 h,随后在110 ℃老化10 h,去离子水清洗干净后在气氛炉中焙烧5 h(温度500 ℃)。
1.3 实验步骤
实验装置见图1。以印染废水的生化出水为处理对象,反应器总容积为2 L,反应器底部填充负载型催化剂,其高度为反应器高度的1/4。
图1
印染废水生化出水被压力泵抽到反应器中,反应器温度通过空气冷凝装置控制恒定,微波装置开启作为反应的起始点。
1.4 有机物分离步骤
印染废水生化出水中的可溶性有机物(DOM)主要有亲水物质、弱疏水物质、非酸疏水物质和疏水酸4类,采用XAD-4和XAD-8树脂(罗门哈斯公司)进行分离,分离过程见图2。依据分离原理,按式(1)~式(4)计算各类DOM含量。
图2
式中:DOM1~DOM4为所取样品的ADMI7.6指标。
1.5 测试指标及方法
COD用国标法测定;AADMI7.6〔7〕采用DR/4000U型可见光分光光度计(美国哈希公司)测定。
2 结果与讨论
2.1 不同体系的处理效果比较
研究催化H2O2、MW/催化H2O2工艺对印染废水生化出水的处理效果。反应条件为:MW为500 W、H2O2为0.09 mol/L,反应温度60 ℃、未调节pH。结果见图3。
图3
2.2 温度对COD去除效果的影响
图4
2.3 微波功率对COD去除效果的影响
图5
2.4 pH对COD去除效果的影响
溶液pH能够影响催化剂表面活性组分的活性,最终影响整个工艺对COD的去除效果。在MW为500 W、H2O2为0.09 mol/L、反应温度为60 ℃的条件下,考察溶液不同初始pH下喹啉和TOC去除率随时间的变化情况。结果表明:溶液pH由3增至7时,组合工艺对印染生化出水COD的去除效果变化不明显,但随着溶液pH继续升高,组合工艺对COD的去除率明显下降。反应体系pH为7时,组合工艺对COD的去除率最高。原因可能是:(1)在酸性或偏酸性环境下,H2O2分解效率低,H2O2的利用率高〔15〕;(2)碱性条件下H2O2分解效率高,H2O2的利用率低〔16〕;(3)碱性条件下,催化剂活性组分的催化性能较低〔17〕。由此确定后续实验pH为7。
2.5 过氧化氢投加量对COD去除效果的影响
图6
2.6 各类有机物去除情况
选择最佳单因素条件作为组合工艺的氧化条件,进行组合树脂分离,分析对各类有机物的去除情况。以AADMI7.6表征时,原水中的疏水类有机物占34.17%,非酸疏水类占53.64%,弱疏水物质占8.78%,亲水性物质占3.41%。实验结果显示,组合工艺对非酸疏水类物质的去除率最高(92.46%);亲水物质去除率最低,可能是由于其含量低,去除难度大;弱疏水物质和疏水类有机物的去除率分别为22.13%、62.45%。
3 结论
(1)以印染废水生化处理二级出水为处理对象,比较了不同工艺的处理效果,微波强化催化H2O2组合工艺具有较大的优势。
(2)采用微波强化催化H2O2组合工艺处理印染废水生化处理二级出水,最佳条件:微波输出功率为500 W、温度为60 ℃、H2O2浓度为理论投加量的1.25倍(基于COD计算)、水力停留时间为18 min,COD去除率为79.89%。
(3)联合树脂分析结果显示,微波强化催化H2O2组合工艺对4类有机物质(基于ADMI7.6)的去除顺序为非酸疏水类物质>疏水酸>弱疏水物质>亲水物质。
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