Removal of heavy metals from dyeing industry wastewater by using eco-friendly absorbents

Abstract

Heavy metals are the very toxic materials for the society. The effluents from textile industries into surface water bodies poses a threat to the aquatic organisms and human health, which is a matter of great concern due to their toxic nature and adverse effect. The small scale dyeing industries generate a large amount of pollution load which in many cases is discharged into environment without any pre-treatment. Dyeing industries releases a harmful heavy metals which is three to four times higher than standard values and most toxic pollutants due to its carcinogenic and teratogenic nature. Several methods have been adopted for the removal of heavy metals from dyeing industry wastewater. These methods are include chemical reduction, precipitation, ion exchange, electrolysis etc., but these process contain more expensive so the small scale industries will not used those process for removal of heavy metals. Among the treatment process, absorption technique is very low cost method. In this study heavy metals from dying industry wastewater is removed by charcoal from various eco-friendly natural available absorbent materials of orange peels, Cavendish banana peels and lemon are used. The effect of various parameters such as dosage of absorbents for the removal of heavy metals, pH and effect of contact time, are studied. From this study, the removal of lead heavy metal by lemon was found to highly efficient 99.8 % at pH =6, contact time 35 min, absorbent dose 0.8 g/l. Removal of zinc heavy metal by lemon 94.39 % at pH =6, contact time 50 min, absorbent dose 0.6 g/l slightly better than banana 91.69 %, contact time 50 min, absorbent dose 1.6 g/l.