竹炭对水溶液中Ni(Ⅱ)的吸附

摘要

在NaAc-HAc缓冲体系中研究竹炭对Ni(Ⅱ)的吸附规律.结果表明:介质pH、粒径大小、初始浓度、反应时间、反应温度对吸附存有影响,在298 K、pH =3.0、初始浓度C0=0.113 mg·mL-1、反应时间为24 h、竹炭粒径为0.2 ～0.4 mm等条件下,每克竹炭的静态饱和吸附量为55.57 mg;与一级动力学相比,竹炭的动态吸附过程更符合二级吸附动力学方程,吸附平衡时间为100 min;竹炭对Ni(Ⅱ)的吸附更好地符合Langmuir吸附等温线,竹炭粒径越小,吸附量越大.吸附热力学参数为:△H =8.19 kJ·mol-1,△S =78.12 J·mol-1K-1,△G298k=-15.08 kJ·mo1-1.此外,还采用红外光谱方法探讨了吸附前后相关化学官能团的变化.研究表明,竹炭可用于去除废水中Ni(Ⅱ)离子.%The adsorption behaviors of Ni( Ⅱ ) ion on bamboo charcoal were investigated with various chemical methods in NaAc-HAc buffer system. The results showed; the sorption was controled by pH, average particle size, initial ion concentration, contact time and temperature and the statically saturated adsorption capacity of bamboo charcoal is 55. 57 mg ·g-1 when the temperature was 298 K, pH was 3. 0, C0 =0. 113 mg · mL-1, contact time was 24 h, particle size was 0. 2 —0.4 mm. Compared with pseudo-first-order kinetics, the adsorption of Ni( II ) ions fitted better with pseudo-second-order kinetics, and the equilibrium time was 100 min. The adsorption of Ni (II) obeyed the Langmuir isotherm better than Freundlich isotherm. The adsorption capacity is greater, when the particle size of bamboo charcoal is smaller. The adsorption parameters of thermodynamic were △H = 8. 19 kJ · mol-1, △S =78. 12 J·mol-1 K-1 and △G298K = — 15. 08 kJ·mol-1. What' s more, the change of chemical functional groups was examined by IR spectrometry. This study demonstrated that bamboo charcoal could be used for the removal of Ni(Ⅱ) ions in water treatment.