【作者】 李怀；

【导师】 李建政；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2014， 博士

【摘要】 制革工业迅速发展、出口创汇的同时，含铬废水造成的环境污染，尤其是水环境污染日益加重。含铬污泥是含铬废水处理过程中的必然产物，也带来日益严重的环境问题。针对我国制革行业二级出水排放达标以及含铬污泥处理处置难的现实问题，开发高效经济的除铬工艺与回收技术迫在眉睫。本文系统研究了磁性氧化石墨烯和磁性氧化石墨烯表面铬离子印迹材料的制备、表征和实际应用，以及含铬污泥中铬的浸出和深度回用技术等科学问题，阐明了氧化石墨烯基纳米复合材料的合成、吸附机制以及实际应用过程中的影响因素和工艺优化策略等问题，建立了含铬污泥中铬的深度资源化回用组合工艺，开发了高效经济的深度除铬工艺及铬资源化回用途径，为皮革行业的可持续发展以及进一步拓宽氧化石墨烯产品和分子印迹技术的应用范围奠定了理论基础。通过共价法成功制备了核–壳磁性氧化石墨烯（Fe3O4@SiO2–GO）。以Fe3O4磁性微球为内核，SiO2为外壳的磁性微球（Fe3O4@SiO2）成功的嫁接在氧化石墨烯表面，负载率为54.45wt%左右。吸附性能研究表明，pH6.0左右时，Fe3O4@SiO2–GO对Cr(III)有较强的富集能力；动态吸附过程为膜扩散和颗粒内扩散联合控制的化学过程；等温吸附过程符合Freundlich吸附等温模型，即不均匀表面的吸附过程，饱和吸附量为4.7mg/g；静电吸附和离子交换过程是Fe3O4@SiO2–GO去除Cr(III)的两种主要机制。以磁性氧化石墨烯为载体，通过表面离子印迹技术成功制备了磁性氧化石墨烯基表面Cr(III)离子印迹材料（Fe3O4@SiO2–GO–IIP）。吸附性能研究表明，其动态吸附过程属于颗粒内扩散控制的化学过程，等温吸附过程符合Langmuir吸附等温模型，即单分子层吸附，饱和吸附量为0.25mg/g；Fe3O4@SiO2–GO–IIP对目标离子具有较强的识别能力，对Cr(III)的吸附选择性是非印迹材料的两倍多；多离子干扰下Fe3O4@SiO2–GO–IIP仍然具有很好的重复利用性和稳定性。4mL0.1mol/L HCl连续5次洗脱即可实现吸附体的完全洗脱。考察了蛋白质、油类（以甘油计）、碳水化合物以及无机盐等4类污染因素对Fe3O4@SiO2–GO–IIP除铬效率的影响。结果表明，蛋白质的存在有利于去除效率的增加，油类、无机盐以及碳水化合物对铬的去除效果有抑制，影响程度的顺序为：蛋白质>油类>无机盐>碳水化合物。随着各污染物负荷的增大，铬的去除效率均呈降低趋势；甘油浓度≤60mg/L、无机盐浓度≤80mg/L以及碳水化合物≤750mg/L可保证Fe3O4@SiO2–GO–IIP对Cr(III)的吸附效果。制革废水二级处理出水中的油类、碳水化合物和无机盐浓度均未达到显著影响离子印迹材料Fe3O4@SiO2–GO–IIP吸附性能的程度。二级出水Fe3O4@SiO2–GO–IIP处理结果表明，在Fe3O4@SiO2–GO–IIP投加量达到4g/L、接触时间为2h的条件下，铬的去除率达90%以上，出水铬含量低于0.3mg/L，达到了GB30486–2013排放标准。Fe3O4@SiO2–GO–IIP吸附饱和后，可采用4mL0.1mol/L的HCl洗脱再生，Fe3O4@SiO2–GO–IIP的吸附性能在6次重复利用实验中基本没有发生变化，说明印迹材料具有较好的重复利用性。含铬污泥资源化回用试验表明，含铬污泥酸浸最佳条件为：湿泥为浸出基质，4%H2SO4为浸出酸，含铬污泥投加量为23.55g/L，接触时间为60min和温度为30°C。浸出率可达20.86mg/g，铬回收率达91.8%。酸浸水的离子交换实验结果表明，最佳吸附剂浓度为6g/L，吸附效率达80%，以10%的硫酸作为解析剂，洗脱效率达95%以上，可实现IRN77树脂的重复利用。2.5%次氯酸钠的预处理能有效提高树脂对酸浸水的吸附效率和连续吸附–解吸附性能，使树脂保持了较好的重复利用性和稳定性能。动态吸附过程属于膜扩散控制的化学过程，等温吸附过程符合Langmuir吸附等温线模型，吸附机制属于吸热的、熵驱动的离子交换。通过本论文研究，建立了二级出水Fe3O4@SiO2–GO–IIP铬回收利用技术；建立了含铬污泥铬的资源化回用体系，有效实现了含铬污泥中资源铬的连续回用。更多还原

【Abstract】 With the rapid development of the leather industry, it has led to an increased discharged wastewater containing heavy metals (Cr(III)), which have detrimental effects on the environment and human health. Chromium sludge was inevitable outcome along with chromium–containing wastewater treatment process, it also brings the environmental pollution seriously. In order to solve effectively the problem of secondary effluent discharge and chromium sludge treatment and disposal in China’s leather industry, the development of chromium removal and recovery technology efficiently become a serious issue.This paper studied the scientific issues systematically about the preparation, characterization and application of Fe3O4@SiO2–GO and Fe3O4@SiO2–GO–IIP and the leaching and depth of reuse technology of chromium on chromium sludge, and clarified that the mechanism of synthesis and adsorption about graphene oxide nanocomposites, and the affecting factors in actual application process and process optimization strategies and other issues, and established the depth of chromium resource reuse combined process on chromium sludge, and developed efficient and economical chromium removal and recovery technology, and also laid a theoretical foundation about the sustainable development of the leather industry and further broadening the graphene oxide–based products and the application of molecular imprinting technology.Fe3O4@SiO2–GO was developed by covalently immobilizing magnetic core/shell Fe3O4@SiO2on GO surfaces. Fe3O4@SiO2magnetic microspheres grafted successfully onto the shell of the graphene oxide surface, and the load was about54.45wt%. Adsorption studies showed that Fe3O4@SiO2–GO had a strong accumulate ability for Cr(III) about pH6.0; dynamic adsorption process was a chemical processes controlled by membrane diffusion and particle diffusion; in good agreement with Freundlich isotherm model, namely uneven surface adsorption process, and adsorption capacity was about4.7mg/g; electrostatic adsorption and ion exchange process were the two principal mechanisms in Cr(III) removal.Fe3O4@SiO2–GO–IIP was prepared successfully with magnetic graphene oxide as the carrier by the surface ion imprinting technique. Adsorption studies showed that dynamic adsorption process was a chemical processes controlled by particle diffusion; in good agreement with Langmuir isotherm model just as the monolayer adsorption, and adsorption capacity was about0.25mg/g; Fe3O4@SiO2–GO–IIP has a strong identified ability for the target ion; the selectivity of Fe3O4@SiO2–GO–IIP was more than twice than that of Fe3O4@SiO2–GO–NIP; at the same time, Fe3O4@SiO2–GO–IIP had good reusability and stability under the multi–ion interference. Elution completely was achieved only through five times consecutive elution using4mL0.1mol/L HCl.The effects of four pollutants such as proteins, oils (glycerol), carbohydrates and inorganic salts on chromium removal on Fe3O4@SiO2–GO–IIP were investigated. The results showed that the presence of the protein in favor for chromium removal, while oils, salts and carbohydrates, played a negative impact, the orders of the impact were: protein>oils>inorganic salt>carbohydrate. With pollutant loads increased, the efficiency of chromium removal showed a decreasing trend. Guiding basis for wastewater pre–assessment were glycerol concentration≤60mg/L, salt concentration≤80mg/L and carbohydrates≤750mg/L. The concentrations of oils, carbohydrates and inorganic salts in secondary effluent did not reach the level of significant impact adsorption properties of ion imprinted materials.The treatment results of secondary effluent showed that when the dosage of Fe3O4@SiO2–GO–IIP reached4g/L at a contact time of2h, chromium removal was up to90%, chromium content in the treated water was less than0.3mg/L meeting fully the GB30486–2013emission standard. Fe3O4@SiO2–GO–IIP reached adsorption saturation can be regenerated using4mL0.1mol/L HCl, and adsorption efficiency had not changed in six repeated experiments, indicating that reuse of imprinted material is better.The leaching results of Cr–sludge showed that the feasible condition for chromium recovery from wet Cr–sludge was as follows:4%H2SO4as the leaching acid, Cr–sludge (dry weight) load23.55g/L, extraction time60min, and reaction temperature30°C. A chromium recovery of20.86mg/g was obtained under the feasible condition with a recovery rate of91.8%. The experimental results of ion exchange about acid–dissolution water showed that the optimum adsorbent concentration about acid–dissolution water was6g/L, and adsorption efficiency was up to80%. The IRN77resin can be eluted effectively up to95%using10%sulfuric acid as eluent, and further realizing IRN77reuse.2.5%NaCLO(v/v) could improve effectively adsorption efficiency and reusability significantly. The dynamic adsorption process was a chemical processes controlled by film diffusion; in good agreement with Langmuir isotherm model; adsorption mechanism was endothermic, entropy–driven ion exchange.Through this research, the technology of chromium recovery from secondary effluent using Fe3O4@SiO2–GO–IIP was established; and a complete Cr–sludge resource reuse system was established, which could make the continuous reuse of chromium from Cr–sludge become a reality.更多还原