The effect of temperature on the biosorption of dyes from aqueous solutions

Abstract

This work is a review of scientific papers on the influence of temperature (T) on the biosorption of various dyes from aqueous solutions and wastewaters. The dyeing process of textiles is usually carried out at high temperatures, and therefore, the wastewater generated there when entering the treatment plant may still be hot. Hence, depending on the climatic conditions of a given region, the biosorption method used for their purification may occur at various temperatures. Most of the papers clearly stated the positive influence of T on biosorption, generally indicating the chemical nature of this process. At the same time, substantial number of authors confirmed the positive effect of T on the biosorption with an initial T-rise from approximately 20 °C to about 30-40 °C range; conversely, at higher temperatures, they indicated a decrease in the biosorption efficiency. Additionally, many authors clearly implied the negative impact of T on the biosorption parameters. They generally envisaged the physical nature of this process, but also indicated its limitation, as there was only a 15%-50% reduction in biosorption efficiency with an increase in T. In addition, an attempt was made to analyse the effect of temperature on the biosorption process, depending on the type of dye. It could then be cautiously suggested that a moderate increase in the T parameter favourably affected the biosorption of the red and reactive dyes.