Aghdam Khaledeh, Panahi Homayon Ahmad, Alaei Ebrahim, Hasani Amir Hesam, Moniri Elham
Environmental Pollution Group, Department of Environment and Energy, Sciences and Research Branch, Islamic Azad University, Tehran, Iran.
Department of Chemistry, Central Branch, Islamic Azad University, Tehran, Iran.
Environ Monit Assess. 2016 Apr;188(4):223. doi: 10.1007/s10661-016-5226-2. Epub 2016 Mar 11.
A poly(allyl acetoacetate)-grafted graphene oxide (GO-GAA) was successfully synthesized using Hummer's method by divinyl sulfone modification and allyl acetoacetate polymerizaton. This novel functionalized graphene oxide was characterized thoroughly by FTIR, XRD, FE-SEM, TEM, and TG-DT analyses. GO-GAA was then employed as an adsorbent for Hg(2+) removal from aqueous solutions. It exhibited higher adsorption capacity with regard to the pristine graphene oxide because of its effective functionalities, especially the dicarbonyl groups which are significant chelating agents. The effects of pH, temperature, and contact time on Hg(2+) adsorption were also investigated. The optimum Hg(2+) adsorption was obtained at pH 4 and T = 20-30 °C. The adsorption isotherm and kinetics were found to follow the Langmuir and pseudo-second-order models, respectively, with a correlation coefficient of 0.99 for both. The calculated maximum adsorption capacity of the adsorbent was 282.7 mg Hg(2+) per unit mass of GO-GAA, which is much more than 56 mg/g of that obtained for GO. The results showed that adsorption reaches up to 95 % of its maximum in less than 2 min. The synthesized GO-GAA as a novel and efficient adsorbent has been regenerated by HNO3 and reused. It retained its performance for Hg(2+) removal for several times and a less than 5 % decrease in removal efficiency was observed after four cycles of adsorption-desorption.
通过二乙烯基砜改性和烯丙基乙酰乙酸酯聚合反应，采用Hummer法成功合成了聚（烯丙基乙酰乙酸酯）接枝的氧化石墨烯（GO-GAA）。通过傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、场发射扫描电子显微镜（FE-SEM）、透射电子显微镜（TEM）和热重-差热分析（TG-DT）对这种新型功能化氧化石墨烯进行了全面表征。然后将GO-GAA用作从水溶液中去除Hg(2+)的吸附剂。由于其有效的官能团，特别是作为重要螯合剂的二羰基，它对原始氧化石墨烯表现出更高的吸附容量。还研究了pH值、温度和接触时间对Hg(2+)吸附的影响。在pH为4和温度T = 20 - 30°C时获得了最佳的Hg(2+)吸附效果。发现吸附等温线和动力学分别遵循朗缪尔模型和准二级模型，两者的相关系数均为0.99。计算得出吸附剂的最大吸附容量为每单位质量的GO-GAA吸附282.7 mg Hg(2+)，这远高于GO所获得的56 mg/g。结果表明，吸附在不到2分钟内达到其最大值的95%。合成的GO-GAA作为一种新型高效吸附剂已通过硝酸再生并重复使用。它多次保持对Hg(2+)的去除性能，在四个吸附-解吸循环后观察到去除效率下降不到5%。
