Hasan Shameem, Ghosh Tushar K, Viswanath Dabir S, Boddu Veera M
Nuclear Science and Engineering Institute, University of Missouri-Columbia, Columbia, MO 65211, USA.
J Hazard Mater. 2008 Apr 1;152(2):826-37. doi: 10.1016/j.jhazmat.2007.07.078. Epub 2007 Jul 28.
Chitosan coated perlite beads were prepared by drop-wise addition of slurry, made of chitosan dissolved in oxalic acid and perlite, to an alkaline bath (0.7 M NaOH). The beads that contained 32% chitosan enhanced the accessibility of OH and amine groups present in chitosan for adsorption of copper ions. The experiments using Cu(II) ions were carried out in the concentration range of 50-4100 mg/L (0.78-64.1 mmol/L). Adsorption capacity for Cu(II) was pH dependent and a maximum uptake of 104 mg/g of beads (325 mg/g of chitosan) was obtained at pH 4.5 when its equilibrium concentration in the solution was 812.5 mg/L at 298 K. The XPS and TEM data suggested that copper was mainly adsorbed as Cu(II) and was attached to amine groups. The adsorption data could be fitted to one-site Langmuir adsorption model. Anions in the solution had minimal effect on Cu(II) adsorption by chitosan coated perlite beads. EDTA was used effectively for the regeneration of the bed. The diffusion coefficient of Cu(II) onto chitosan coated beads was calculated from the breakthrough curve and was found to be 2.02 x 10(-8) cm(2)/s.
壳聚糖包覆珍珠岩珠粒的制备方法是，将由溶解在草酸中的壳聚糖和珍珠岩制成的浆料逐滴加入到碱性浴（0.7 M NaOH）中。含有32%壳聚糖的珠粒提高了壳聚糖中存在的羟基和胺基对铜离子吸附的可及性。使用铜（II）离子进行的实验在50 - 4100 mg/L（0.78 - 64.1 mmol/L）的浓度范围内进行。对铜（II）的吸附容量取决于pH值，在298 K时，当溶液中的平衡浓度为812.5 mg/L且pH为4.5时，珠粒的最大吸附量为104 mg/g（壳聚糖为325 mg/g）。XPS和TEM数据表明，铜主要以铜（II）的形式被吸附，并附着在胺基上。吸附数据可以拟合到单点位朗缪尔吸附模型。溶液中的阴离子对壳聚糖包覆珍珠岩珠粒吸附铜（II）的影响最小。EDTA可有效地用于床层的再生。根据穿透曲线计算出铜（II）在壳聚糖包覆珠粒上的扩散系数，结果为2.02×10⁻⁸ cm²/s。
