Khraisheh M A M, Al-Ghouti M A, Allen S J, Ahmad M N M
Department of Civil and Environmental Engineering, University College, London.
Water Environ Res. 2004 Nov-Dec;76(7):2655-63.
This work is an investigation on the use of manganese oxides-modified diatomite (MOMD) for the removal of color from textile wastewaters. The modification of the diatomite was carried out by treatment with manganese oxides; delta-bimessite type resulted. The surface area, pH(ZPC), Fourier transform infrared (FTIR), and scanning electron microscopy of MOMD were studied. The influence of concentration, pH, particle size, and temperature on the adsorption capacities of methylene blue (MB) and hydrolyzed reactive black (RB) and reactive yellow (RY) was investigated. Key thermodynamic parameters such as deltaH degrees, deltaS degrees, and deltaG degrees were also determined. The deltaH degrees of MB and hydrolyzed RB and RY was +94.64, -143.1, and -38.78 kJ/mol, respectively, whereas the deltaG degrees values of -17.68, -27.93, and -23.26 kJ/mol were obtained, indicating a spontaneous process with low activation-energy requirements. The findings further indicated that coulomb interaction, molecular size, and orientation of the dye and its surface charge played an important role in the adsorption and attachment of the dyes to the bimessite layers of MOMD.
本研究旨在探讨氧化锰改性硅藻土（MOMD）用于去除纺织废水颜色的效果。通过用氧化锰处理对硅藻土进行改性，得到了δ型水钠锰矿。研究了MOMD的比表面积、零电荷点（ZPC）、傅里叶变换红外光谱（FTIR）和扫描电子显微镜。考察了浓度、pH值、粒径和温度对亚甲基蓝（MB）、水解活性黑（RB）和活性黄（RY）吸附容量的影响。还测定了诸如ΔH°、ΔS°和ΔG°等关键热力学参数。MB、水解RB和RY的ΔH°分别为+94.64、-143.1和-38.78 kJ/mol，而ΔG°值分别为-17.68、-27.93和-23.26 kJ/mol，表明这是一个具有低活化能需求的自发过程。研究结果进一步表明，库仑相互作用、染料的分子大小和取向及其表面电荷在染料吸附到MOMD的水钠锰矿层并附着的过程中起着重要作用。
