Title: Assessing treatment of lead (Pb II) from industrial wastewater on dried bulbs of water hyacinth: adsorption capacity, isotherm and kinetic study

Authors: Tiyasha Kanjilal; Chiranjib Bhattacharjee; Siddhartha Datta

Addresses: Bioprocess Engineering Laboratory, Chemical Engineering Department, Jadavpur University, 188, Raja S.C. Mallick Road, Kolkata-700032, West Bengal, India ' Bioprocess Engineering Laboratory, Chemical Engineering Department, Jadavpur University, 188, Raja S.C. Mallick Road, Kolkata-700032, West Bengal, India ' Bioprocess Engineering Laboratory, Chemical Engineering Department, Jadavpur University, 188, Raja S.C. Mallick Road, Kolkata-700032, West Bengal, India

Abstract: Remediation through aquatic macrophytes treatment system for the removal of noxious contaminants from wastewater is an emerging environmental protection technique. The dried and acid-alkali treated bulbs of water hyacinth (WHB) having high porosity and O₂-filled functional groups were utilised to treat Pb(II) from industrial wastewater. Characterisation of WHB with FESEM, XRD and FTIR exhibited the presence of several carboxyls, hydroxyl, ketonic, aldehydes and other O₂-filled functional groups showing WHB adsorption with highest monolayer capacity of (Q_m) 38.614 mg/g. WHB adsorption directed towards the pseudo-second order kinetics and Langmuir isotherm mechanism. The study also emphasised effective regeneration of WHB using HNO₃, NaOH and vacuum dry. The bio-sorption mechanism was observed to be endothermic spontaneous reaction process, with ΔG decreased from -0.71 to -8.53 with increasing temperature. With optimised and controlled process conditions, only 5.0 g L⁻¹ of WHB bio-sorbent could significantly treat about 85.3% of 100 mg L⁻¹ of Pb(II) within 120 minutes at pH 7.0 and 30°C. Also a comparative optimisation study of ANN and RSM were used to predict the WHB bio-sorption bioprocess. Therefore, WHB have efficient potential to be commercially applicable as an environmental-friendly and economical bio-sorbent for treatment of Pb(II) from solutions and effluent from paint industry.

Keywords: water hyacinth bulbs; Pb(II) removal; adsorption; kinetics; optimisation; isotherm.

DOI: 10.1504/IJETM.2017.086468

International Journal of Environmental Technology and Management, 2017 Vol.20 No.1/2, pp.101 - 127

Accepted: 21 May 2017
Published online: 10 Sep 2017 *

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