ABSTRACT
The adsorption study was carried out to evaluate the effects of various pretreatments on tea waste (TW) for the removal of Ni (II) metal ions from synthetic waste water. The tea water was chemically treated with 0.1M different NaOH, Na2S, HCHO, KOH, Na2CO3, H2C2O4, HCL, H2S04, H3PO4, HNO3 solutions. It was observed that certain chemicals NaOH, Na2S, HCHO, KOH, Na2CO3 increased (92.1%-74.8%) the removal efficiency substantially whereas other chemicals H2C2O4, HCL, H2S04, H3PO4, HNO3(24.9%-0.6%) reduced it drastically as compared with untreated tea waste 65.1%. The removal efficiency with NaOH and Na2S pretreatments was 92.1% and 92%. These two pretreatments were further compared by changing different reaction parameters. These were compared by changing the pH value, contact time, adsorbent dose and initial Ni(II) ion concentration along with the study of their equilibrium conditions. The Langmuir model described the adsorption isotherm best. The Langmuir adsorption capacity was found to be 30.31 mg/g for ATTW and 27.03 mg/g forSTTW at pH 6. The pretreatment with 0.1 M NaOH was found to be the best treatment method for the removal of Ni (II) metal ions from synthetic waste water
