氧化石墨烯处理选矿废水过程的诱导疏水机制及调控原理

The heavy metal ions from the discharge of the untreated beneficiation wastewater can result in serious environmental pollution. The heavy metal ions from untreated beneficiation wastewater will negatively affect the flotation performance. Graphene oxide (GO) is an ideal sorbents in the removal of heavy metal ions, due to its large theoretical surface area, high adsorption capacities and recyclability. To recycle the GO in low cost and large scale after removal of heavy metal ions, this proposed project will carry out the investigation on the.co-adsorption behavior of amine collector and heavy metal ion on GO and its regulation mechanism,the results of which will provide the theory basis for recovery of GO. In this project, the GO with different oxidation degree and different size dimension will be prepared，the physic-chemical properties of GO will be characterized by modern analysis determination techniques, and the adsorption performance as well as wettability of GO related to the distribution of oxygen-containing functional group will be determined. Besides, this project will.study the co-adsorption behavior of typical collectors with heavy metal ions on graphene oxide sheet, and influence of GO’s induced hydrophobicity by collector on interfacial property, heavy metal ions adsorption property, the agglomeration behavior. Aims to resolve the decline of adsorption capacity of GO for heavy metal ions, this proposed project strengthen the co-adsorption ability of GO for amine collector and heavy metal ions by adjusting the distribution of oxygen-containing functional group, oxidation degree, size dimension as well as solution chemistry condition. Finally, to explore a new method inducing hydrophobicity of GO by residual collector and removal of metal ions from beneficiation wastewater by air flotation.

选矿废水中重金属离子未经处理排放将导致严重的环境污染，直接回用可能恶化浮选过程。本课题针对氧化石墨烯（GO）吸附脱除重金属离子后难以低成本大规模回收的技术问题，开展胺类捕收剂诱导GO疏水时与金属离子在GO表面共吸附行为调控研究，为气浮法回收GO提供理论基础。课题首先制备不同氧化度、不同尺寸的GO，采用现代的分析测试手段表征其物化性质，确定GO含氧官能团分布与吸附性能、润湿性的关系；研究捕收剂与重金属离子在GO界面的共吸附行为，及捕收剂对氧化石墨烯诱导疏水作用对其界面性质、重金属离子吸附性能、团聚行为的影响规律。针对GO诱导疏水时重金属离子吸附能力下降的情况，通过调控GO表面含氧官能团、氧化度、尺寸大小及溶液化学条件，强化其对捕收剂与重金属离子的共吸附能力。最终，形成GO诱导疏水－气浮法脱除选矿废水中重金属离子的新技术。

针对选矿废水中残留浮选药剂、金属离子未经处理排放将导致环境污染的问题，本研究分别制备了氧化石墨烯（GO）、氧化石墨烯/聚乙烯亚胺凝胶（GO/PEI凝胶）、负载铅离子GO/PEI凝胶，以十二胺、油酸钠、丁基黄药为浮选药剂代表，Ca2+，Mg2+，Al3+，Fe3+为金属离子代表，开展了超声剥离轻度氧化石墨制备氧化石墨烯技术研究；氧化石墨烯对十二胺（DACl）吸附性能研究；DACl在 GO表面吸附机理研究；氧化石墨烯/聚乙烯亚胺水凝胶制备技术研究；氧化石墨烯/聚乙烯亚胺凝胶对油酸钠的吸附行为及机理研究；各种离子对氧化石墨烯/聚乙烯亚胺凝胶吸附油酸钠影响研究；氧化石墨烯/聚乙烯亚胺凝胶吸附丁基黄药性能研究；负载铅离子的氧化石墨烯/聚乙烯亚胺凝胶的制备及其吸附丁基黄药性能研究。研究结论如下：.本项目采用低成本晶片状石墨(FG)制备而得的氧化石墨烯（GO）可作为十二胺（DHCl）处理的高效吸附剂，研究表明DHCl在GO上主要通过氢键作用和静电作用吸附，该吸附过程属于自发过程和吸热过程。DHCl在GO上吸附后诱导GO疏水，形成了气浮法回收GO吸附剂的关键技术。.确定了GO/PEI凝胶最优合成条件，且各项表征结果证明合成产物为目标产物。氧化石墨烯/聚乙烯亚胺凝胶对油酸钠的吸附动力学和吸附等温线结果表明该过程为物理吸附和多层吸附为主。吸附机理研究结果表明GO/PEI凝胶吸附油酸钠可能还存在化学吸附。.各种离子对氧化石墨烯/聚乙烯亚胺凝胶吸附油酸钠影响研究结果表明当油酸钠与Ca2+、Mg2+、Al3+或者是与阴离子NO3-共存时，这些离子会与油酸钠在GO表面产生竞争吸附，即GO对油酸钠的吸附量下降；当油酸钠与K+或者是与阴离子PO43-或SO42-共存时，在低浓度下，可以产生协同吸附作用；当油酸钠与阴离子CO32-共存时，则是在较高浓度时，可以产生协同吸附作用。.GO/PEI凝胶与负载铅离子的氧化石墨烯/聚乙烯亚胺凝胶对丁基黄药的吸附实验对比发现，同样是用于用于吸附100mg/L丁基黄药溶液，负载铅离子的GO/PEI凝胶对丁基黄药的吸附可以达到382mg/g远高于GO/PEI凝胶（101.48mg/g）。