Adsorption and kinetic study of spent tea leaves on dye

Abstract

Coloured effluents from industrial activities have negative impact on the environment and also human health. Many efforts have been done to decolourise such effluent. The conventional solution is adsorption by using activated carbon. However, researchers are now focusing on natural adsorption to rely less on manmade adsorbent. Natural adsorbent is also a studied in order to convert natural waste into a pollution control solution. This study focused on spent tea leaf. Tea is a favourite past time beverage for Malaysian. The waste amount created by spent tea leaf is an untapped source of agricultural waste waiting to be use. Spent tea leaf has been studied for its potential ability as an adsorbent. However, this study was emphasised on investigating the behaviour of spent tea leaf with different particle size on Methylene Blue (MB) dye in aqueous. The spent tea leaf were collected from stall and decoloured by boiling it thoroughly, it was later crushed and sieved into different particle size. Effects of adsorbent dosage, dye concentration, particle size, and contact time have been studied. This has resulted in the highest efficiency of colour removal of 93.9% at pH 7, 50ppm of MB concentration, 0.2g of spent tea leaf with particle size of <150µm at 30 minutes. Langmuir and Freundlich isotherm models were tested on the adsorption data and the adsorption process best described by Langmuir isotherm. Maximum adsorption rate was at 140.845 mg/g.