Preparation of Quaternized Lignin Derived from Oil Palm Empty Fruit Bunches and its Flocculation Properties

Abstract

Quaternized lignin-based flocculant (QL) was prepared by a single-step reaction of an extracted lignin (EL) derived from oil palm empty fruit bunches (OPEFB) with 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) under alkaline condition. The performance of QLs was studied for various β values (molar ratios of CHPTAC to phenylpropanoid unit of lignin), flocculant dosages, pH values, kaolin concentrations, slow mixing rates and sedimentation times. The QL10 achieved the highest turbidity removal efficiency (ε_t) with increasing flocculant dosage, pH and kaolin concentration to the optimal conditions of 5 mg L⁻¹, pH 7 and 1000 mg L⁻¹, and required 20 min of sedimentation time at all the mixing rates tested. The flocculation kinetics agreed well with the particle collision model. The QL10 has good sludge dewatering properties compared to the alum. It also showed encouraging results in water quality analysis for sewage wastewater flocculation in comparison to that of the alum. This indicates the potential application of QL in treating water and wastewater.

Keywords:

• Oil palm empty fruit bunches
• quaternized lignins
• flocculation
• kinetics study
• sludge dewatering

Additional information

Funding

The financial supports from the Ministry of Science, Technology and Innovation (MOSTI), Malaysia under the eScience Research Program (Project No. 4S071), the MyBrain15 scholarship from the Ministry of Higher Education (MOHE), Malaysia, technical supports from the Indah Water Konsortium (IWK) Berhad, Syarikat Air Johor (SAJ) Berhad, and the Universiti Teknologi Malaysia for Postdoctoral Fellowship Scheme (PDRU 03E92) and (PDRU 04E29) are gratefully acknowledged.