论文以固态电子垃圾和金电镀废液中金资源的回收为目标，针对现有废弃金资源回收效率低、选择性差等难题，利用氧化石墨烯（GO）具有大比表面积和表面性质可控调节的特点，制备了对不同金离子具有高吸附容量的金吸附材料，建立了从电子垃圾和金电镀废液中高容量、精准选择性回收金资源的方法。进一步地，利用石墨烯和金较高的光热转换效率，探索了石墨烯和回收金资源在光热水净化过程中的再利用，以缓解淡水短缺问题。论文取得的主要创新性结论包括：（1）采用抗坏血酸还原GO制备了还原氧化石墨烯（rGO）材料。发现rGO对10 ppm和1 ppm金离子的吸附容量分别达1850 mg/g和 1180 mg/g。揭示了rGO对金离子的还原吸附机制，提出rGO的微观结构决定了其对金的吸附性能，其中石墨烯微区贡献电子将Au(Ⅲ)还原为金属态Au(0)，而氧化区为rGO提供了良好的分散性，使得保证了rGO的大比表面积及对金离子的高效吸附。通过调控rGO含氧官能团的质子化过程，在14种金属元素共存条件下，实现了rGO从电子垃圾中精准地提取回收金。进一步地，发展了基于rGO薄膜的连续金回收方法，可高效、连续地从电子垃圾中回收金资源。（2）将负载于三聚氰胺海绵上的rGO，用于吸附回收电子垃圾中的废弃金资源，获得了rGO/Au/三聚氰胺海绵杂化材料（GRAMS）。结合rGO、金的高光热转换效率和三聚氰胺海绵的优异机械性能，开发出高效的光热水蒸发材料及器件。GRAMS具有良好的长期稳定性、优异的可洗性和便携性。在1个太阳光强度照射下，GRAMS的水蒸发速率达到3.55 kg/m2/h。由GRAMS组装的树状蒸发器件在户外环境下的水蒸发速率达9.36 kg/m2/h，并可以将污染水转化为符合世界卫生组织标准的饮用水。（3）制备了胺基功能化的GO，提出了光热耦合增强金吸附的方法，实现了对难回收一价金离子Au(I)的高效吸附。针对现有材料不能高效回收电镀液中Au(I)离子的难题，采用聚乙烯亚胺改性的GO材料（GO-PEI）作为Au(I)吸附剂，其对10 ppm Au(I)的吸附量达到879 mg/g，揭示了胺基基团对Au(I)的还原吸附和静电吸附机制。模拟电镀废液的金回收实验证明，电镀液中常见共存离子并未影响GO-PEI对Au(I)的高选择性和高吸附容量。在此基础上，利用GO-PEI的光热效应提高金吸附温度，在1个太阳光强照射下将吸附容量提升至1652 mg/g，吸附容量远高于现有吸附材料。

Gold is a good electrical conductor and is widely used in electronic products and consumer goods. Gold resources are limited, so the recycling of waste gold resources is essential for sustainable development. Aiming to extract gold in solid e-waste and gold electroplating wastewater, this dissertation uses graphene oxide (GO), which has a large specific surface area and controlled surface properties, to prepare gold adsorbents with high adsorption capacity for different gold ions. High-capacity and precise extraction methods for gold resources were established. Furthermore, using the high photothermal conversion efficiency of graphene and gold, the reuse of graphene and recycled gold in the photothermal water purification application was explored to alleviate the problem of fresh water shortage. The main conclusions of the dissertation are:(1) We found that reduced graphene oxide (rGO) provides an ultrahigh capacity and selective extraction of Au(III) present in ppm concentrations (1,850 mg/g and 1,180 mg/g to 10 ppm and 1 ppm gold). The excellent gold extraction performance is accounted to the graphene areas and oxidized regions of rGO. The graphene areas spontaneously reduce Au(III) to metallic gold, and the oxidized regions allow good dispersibility of the rGO material so that efficient adsorption and reduction of gold ions at the graphene are-as can be realized. By controlling the protonation of the oxidized regions of rGO, gold can be extracted exclusively, without contamination by the other 14 co-existing ele-ments typically present in e-waste. These findings are further exploited to demonstrate recycling gold from real-world e-waste with good scalability and economic viability, as exemplified by using rGO membranes in a continuous flow-through process. (2) Considering the good photothermal effect of rGO and gold, we propose to reuse the recycled gold resources and realize the efficient photothermal water evaporation material preparation and water evaporation applications. The photothermal material was made by simultaneously incorporating graphene and gold particles grown from e-waste in a melamine sponge (MS), hereafter referred to as “GRAMS” (Graphene-Recycled Au-Melamine Sponge). In addition to a high evaporation rate (3.55 kg/m2/h under 1-sun irradiation), it shows good long-term stability, excellent washability and portability. Furthermore, we have assembled a GRAMS-based evaporator device that has a high evaporation rate of 9.36 kg/m2/h under outdoor sunlight and provides purified water that meets the World Health Organization drinking water standards.(3) The amine-functionalized GO was prepared, and the photothermal coupling enhanced gold adsorption method was proposed to realize the high-efficiency adsorption of Au(I) that is difficult to recycle. Given the problem that existing materials cannot ef-ficiently extract Au(I) from gold electroplating solutions, the GO-polyethyleneimine (GO-PEI) was prepared as the Au(I) adsorbent. The adsorption capacity at 10 ppm Au(I) is 879 mg/g. The mechanism of reductive adsorption and electrostatic adsorption of Au(I) by amine groups is revealed. The Au(I) extraction experiment of simulated gold electroplating wastewater shows that the high selectivity and adsorption capacity of Au(I) were not affected by the common co-existing ions in gold electroplating wastewater. Furthermore, the photothermal effect of GO-PEI was used to increase the gold adsorp-tion temperature, and the adsorption capacity was increased to 1652 mg/g under the 1-sun irradiation, which was much higher than the existing adsorbents.