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【答案】应助回帖
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七月love: 金币+226, 翻译EPI+1, ★★★★★最佳答案 2017-04-06 11:35:49
中文：用扫描电镜观察发现，AFSS（吸附剂）表面有大量的CCS，它具有还原性，可能会使溶液中的 Cr(VI)还原成Cr(III)。Cr(III）会与吸附剂中的官能团（如巯基）发生离子交换，达到铬离子吸附在吸附剂上的目的。pH较低时，AFSS表面包围大量的氢离子，这有利于还原反应的进行。随着pH升高，氢离子浓度降低，还原反应减弱， Cr(VI)吸附体系中 Cr(VI)还原成Cr(III)的数目减少，吸附剂吸附Cr(VI)的能力下降。此外，氢离子浓度过高也会与溶液中产生的Cr(III)竞争吸附剂的反应活性位点，这同样也会在一定程度上阻碍Cr(VI)还原成Cr(III)。因此，吸附剂对Cr(VI)的最佳吸附pH为4.0。
It can be seen from the SEM results that there were many CCS on the surface of AFSS (adsorbent), which may reduce the Cr(VI) in the solution into Cr(III). At the meantime, Cr (III) may react with the mercapto groups in the adsorbent to achieve the adsorption of chromium ions on the adsorbent. As the pH value increases, and the concentration of H+ decreases, the reduction reaction weakens. Consequently, the amount of the Cr(VI) reduced into Cr(III) decreases, and the capability of the adsorbent for adsorbing Cr(VI) decreases. In addition, if the concentration of H+ is excessively high, the H+ will compete with the Cr(III) formed in the solution for the reactive sites on the adsorbent, which hinders the reduction of Cr(VI) into Cr（III） to some extent. As a result, the optimal pH value for the adsorbent for adsorbing Cr(VI) is 4.0. |
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