The removal of Hg from contaminated aquatic media is of major importance, taking into consideration the highly toxic character of the element. One of the most promising water treatment technologies is adsorption by low cost adsorbents, such as activated carbon produced by agricultural byproducts. In this study, activated carbon in granular form (GAC) was produced using pistachio shells from Aegina Island (Greece). Two main GAC products have been synthesized. The first one was chemically activated using ZnCl₂. The second one was further treated with Na₂S in order to introduce S atoms on the functional groups. The effectiveness of synthesized GAC products for Hg removal was evaluated by conducting batch equilibrium and kinetic experiments. It was found that sulfurization was able to increase by a factor of more than 2 the adsorptive capacity of activated carbon. Namely the maximum adsorption capacity was 73 mg/g for the simple GAC and increased up to 166 mg/g for the S-modified product. The kinetics of adsorption was described with almost equivalent precision using the pseudo-first and the pseudo-second order models, a behavior which is often observed in adsorption experiments, depending on the experimental conditions. The value of activation energy E_A was found to be negative (− 18.8 kJ/mol) in the case of simple GAC and positive (8.27 kJ/mol), in the case of S-modified GAC, suggesting that Hg adsorption on the modified carbon follows a different mechanism, closer to chemisorption processes.

考虑到元素的剧毒特性，从受污染的水生介质中去除汞非常重要。最有前途的水处理技术之一是利用低成本吸附剂进行吸附，例如农业副产品产生的活性炭。在这项研究中，使用来自希腊埃伊纳岛的开心果壳生产了颗粒状活性炭（GAC）。已经合成了两种主要的GAC产品。第一个是使用ZnCl ₂化学活化的。第二个用Na ₂进一步处理S是为了在官能团上引入S原子。通过进行批平衡和动力学实验，评估了合成的GAC产物去除汞的有效性。发现硫化能够将活性炭的吸附能力提高两倍以上。即，对于简单的GAC，最大吸附容量为73 mg / g，对于S-改性产物，最大吸附容量增加至166 mg / g。吸附动力学是使用拟一级和拟二级模型以几乎相同的精度描述的，这种行为通常在吸附实验中观察到，具体取决于实验条件。活化能E _A的值 在简单的GAC中发现为负（− 18.8 kJ / mol），在S修饰的GAC中发现为正（8.27 kJ / mol），这表明修饰碳对Hg的吸附遵循不同的机理，化学吸附过程。