Adsorption of phenol from wastewater using modified layered double hydroxide clay

Abstract

Phenol and its derivatives are some of the organic pollutants found in wastewater and they pose health risks to human beings and animals if left untreated. This work investigates the use of modified Layered Double Hydroxide clay as an adsorbent for removal of phenol from wastewater. High exchange capacities, capability to be modified with surfactants and through calcination, and the ability to regenerate are some of the properties of the clay reported in literature which make it an ideal adsorbent for phenol removal from wastewater. Modification of neat clay with silane increased the adsorption percentage from 6 % to 19 %, however the extent of adsorption was reduced from 87 % to 35 % when calcined clay was coated with a silane material. Calcination of the clay increased its BET surface area from 8.71 m2/g to 29.74 m2/g. The adsorption kinetics were best fitted by the pseudo second order model. The equilibrium isotherms which best fitted the adsorption data were the Freundlich isotherm and the Three Parameter Langmuir-Freundlich isotherm. The maximum adsorption capacity of 59.1 mg/g was observed using the Three Parameter Langmuir-Freundlich isotherm.