Babel Sandhya, Kurniawan Tonni Agustiono
Environmental Technology Program, Sirindhorn International Institute of Technology (SIIT), Thammasat University, P.O. Box 22, Thammasat Rangsit PO, Pathumthani 12121, Thailand.
Chemosphere. 2004 Feb;54(7):951-67. doi: 10.1016/j.chemosphere.2003.10.001.
In this study, the technical feasibility of coconut shell charcoal (CSC) and commercial activated carbon (CAC) for Cr(VI) removal is investigated in batch studies using synthetic electroplating wastewater. Both granular adsorbents are made up of coconut shell (Cocos nucifera L.), an agricultural waste from local coconut industries. Surface modifications of CSC and CAC with chitosan and/or oxidizing agents, such as sulfuric acid and nitric acid, respectively, are also conducted to improve removal performance. The results of their Cr removal performances are statistically compared. It is evident that adsorbents chemically modified with an oxidizing agent demonstrate better Cr(VI) removal capabilities than as-received adsorbents in terms of adsorption rate. Both CSC and CAC, which have been oxidized with nitric acid, have higher Cr adsorption capacities (CSC: 10.88, CAC: 15.47 mg g(-1)) than those oxidized with sulfuric acid (CSC: 4.05, CAC: 8.94 mg g(-1)) and non-treated CSC coated with chitosan (CSCCC: 3.65 mg g(-1)), respectively, suggesting that surface modification of a carbon adsorbent with a strong oxidizing agent generates more adsorption sites on their solid surface for metal adsorption.
在本研究中，使用合成电镀废水通过批次研究考察了椰壳炭（CSC）和商业活性炭（CAC）去除六价铬的技术可行性。两种粒状吸附剂均由椰壳（椰子属）制成，这是当地椰子产业产生的一种农业废弃物。还分别用壳聚糖和/或氧化剂（如硫酸和硝酸）对CSC和CAC进行了表面改性，以提高去除性能。对它们的铬去除性能结果进行了统计比较。显然，用氧化剂进行化学改性的吸附剂在吸附速率方面表现出比原样吸附剂更好的六价铬去除能力。经硝酸氧化的CSC和CAC的铬吸附容量（CSC：10.88，CAC：15.47 mg g⁻¹）分别高于经硫酸氧化的（CSC：4.05，CAC：8.94 mg g⁻¹）和涂覆壳聚糖的未处理CSC（CSCCC：3.65 mg g⁻¹），这表明用强氧化剂对碳吸附剂进行表面改性会在其固体表面产生更多用于金属吸附的吸附位点。
