| Summary: | 碩士 === 國立成功大學 === 環境工程學系碩博士班 === 94 === Copper is an important pollutant in the wastewater of metal treatment and semi-conductor industries. Among the wastewater treatment processes, adsorption is a relatively inexpensive method for the removal of copper from wastewater. The aim of this research is to develop a low cost adsorbent for the application in the wastewater treatment.
Several diatomite were employed in this study as raw materials of adsorbent. After surface modification, the adsorbent was used in adsorption experiments of copper and other heavy metals in aqueous phase. The surface properties of virgin diatomite and modified diatomite were tested with scanning electronic microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), X-ray fluorescent analysis (XRF), specific surface area, and pore size distribution. Based on the analytical results, the adsorbent was relatively porous, the surface of diatomite was SiO2 (Quartz), and the major elements were silicon, oxygen, aluminum, and iron.
The adsorption experiments reflect that about 48 hours are needed for equilibrium to reach for the adsorption of copper onto the modified diatomite, and about 24 hours are needed for desorption. Both Langmuir and Freundlich isotherm equations are able to describe the adsorption capacity for the copper/modified diatomite systems. The adsorption capacity at pH = 5.5 and initial concentration = 10 mg/g of copper, was about 10 mg/g for virgin diatomite. After modification, the adsorption capacity increased by 5 times, and became 52 mg/g. After desorption and re-activation, the adsorption capacity for the modified diatomite still had 40 mg/g, indicting the potential of application in the wastewater treatment.
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