Novel design of microsphere adsorbent for efficient heavy metals adsorption

摘要

The fabrication of high-efficiency and low-cost adsorbent for the wastewater treatment is a challenging task. In this study, a hollow sphere adsorbent was synthesized from solid waste coal gangue through a facile spray drying method and subsequent calcination. The structure of the synthesized coal gangue microsphere (CM) have been characterized by multimethods including X-ray diffraction, scanning electron microscope, Fourier transform infrared, and others. The factors influencing the adsorption for Cu2+ and Pb2+ by CM were also investigated systemically; pH between 6 and 8 was found to be optimal for Cu2+ and Pb2+ adsorption. The isotherm and kinetic analysis reveal that the adsorption process could be well represented by Langmuir and pseudo-second-order model with a higher R-2 and low chi(2) value. According to Langmuir model, the maximum adsorption capacity was calculated to be 6.570 and 18.904 mg/g for Cu2+ and Pb2+ at 25 degrees C, respectively. The adsorption mechanism was proposed to contain not only the surface reaction process, but also the diffusion process. Consequently, the economic and environmental benefits make CM a promising adsorbent in wastewater treatment.