Milli-sized calcium alginate sorbent supporting the dye waste – calcium fluoride hybrid for adsorption of organic contaminants

Abstract

A new kind of milli-sized sorbent—calcium alginate supporting a weak acidic pink red B (APRB)–calcium fluoride nano-sized hybrid—was prepared. The micro-structure of the hybrid and adsorbent were characterized, and its adsorption capacity for organic contaminants, e.g. dyes, PCBs and microcystin (MC)-LR, was investigated. Cationic dyes were adsorbed selectively via charge attraction, with a saturation capacity of 188 mg of cationic red 3R per gram of the milli-sized adsorbent. However, the adsorptions of PCBs and MC-LR corresponded to the octanol–water partition law, and their partition coefficients were calculated to be 7788.6 mg kg−1 for PCB029, 13325 mg kg−1 for PCB101, 434.6 mg kg−1 for PCB180, and 369.2 mg kg−1 for MC-LR. When the milli-sized adsorbent was used in the treatment of two concentrated dye wastewaters and two polluted ground waters, the removal of the colored substances, chemical oxygen demand (COD), and concentration of PCBs and MC-LR were satisfactory. In the synthesis of the materials, all of the reactants are easily available and harmless to the environment, and APRB may be obtained from concentrated APRB-containing wastewater instead. The development of the milli-sized hybrid adsorbent provided liquid–solid separation, for favorable use in engineering. It will play an important role in the treatment of concentrated wastewater and the remediation of ground water contamination.