Competitive adsorption for binary mixture of 4-nitrophenol and phenol on RSTA using GAC

Abstract

Adsorption characteristics of a reverse stratified tapered adsorber (RSTA) system and competitive adsorption for phenol and 4-nitrophenol were investigated. In this study, a novel technology, RSTA, was introduced and compared with a conventional cylindrical adsorber (CA). The optimum study of RSTA in a single-solute system with phenol for size distribution, mean velocity and optimum angle was conducted to satisfy environmental criteria and reduce granular activated carbon (GAC) treatment costs. The competitive adsorption efficiency of RSTA and CA was also compared in a binary solute system with phenol and 4-nitrophenol. In the results of single-solute experiment, breakthrough time of RSTA was increased by 30-50% over conventional CA. The mean bed velocity was 19.10 cm/min and the optimum angle of RSTA was decided to 3°. Adsorption efficiency was increased with increasing GAC dose and the number of GAC layers. The affinity of competitive adsorption was significantly increased with decreasing GAC dose and increasing adsorbate concentration. The RSTA can be considered to provide an increase in breakthrough time with decreasing flow rate and increasing the number of layers. Water and wastewater plants processing large volumes of water can realize significant savings in capital and operation costs by utilizing this type of operation.