Effects of pH and temperature on isotherm parameters of chlorophenols biosorption to anaerobic granular sludge.

As the most important parameters affecting the biosorption, pH and temperature were studied in this paper in order to more completely understand their effects on chlorophenols' biosorption onto anaerobic granular sludge. Sorption isotherms of 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP) at various temperatures were determined; the data of 4-CP could be simulated by Langmuir model, while the data of 2,4-DCP could only be reproduced by Freudlich equation. The uptake capacity of 4-CP and 2,4-DCP could reach 1.5mgg(-1) and 5.04mgg(-1) when 2,4-DCP concentration was 90mgL(-1) and 4-CP concentration was 107mgL(-1), respectively. 2,4-DCP was more strongly adsorbed onto the anaerobic granular sludge than 4-CP, which might be correlated with the numbers of chlorine substitute. The Experiments studying pH effects showed that the adsorption capacity of 4-CP and 2,4-DCP was quite pH dependent and increased with decrease in pH.