A Study Of Polydadmac Induced Flocculation In Treatment Of Pulp And Paper Mills Wastewater
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Date
2011-10
Authors
Ahmad Razali, Mohd Amin
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
This study investigates the effect of polyDADMAC on treating pulp and paper mills
wastewater. PolyDADMAC was synthesized with different monomer
concentration. Fourier Transform Infrared Spectroscopy (FTIR) was conducted to
confirm the structure of polyDADMAC. Ubbelohde Viscometer was used to
determine intrinsic viscosity and these values were used to determine molecular
weight by employing the Mark Houwink equations. Molecular weight and intrinsic
viscosity increased with increasing of monomer concentration (1.37 to 1.87
M). Beyond the monomer concentration 1.87M the molecular weight began to
decrease. Subsequently, the jar test was conducted using polyDADMAC produced
on kaolin suspensions and factory wastewater. The effectiveness of polyDADMAC
on treating kaolin suspensions as simulated wastewater was conducted before tested
in actual wastewater. Flocculation tests for kaolin suspension were carried out at
constant polyacrylamide (PAM) dosage of 0.2 mg L-1 while the dosage of
polyDADMAC was varied from 0.2 - 50 mg L-1. Flocculation tests for pulp and
paper mills were divided in three studies. Initially, the effect of molecular weight of
polyDADMAC alone then the effect of polyDADMAC dosages in hybrid system
with PAM and finally the effect of different molecular weight of polyDADMAC in
hybrid systems with PAM. Dosage range was from 0.4 - 2.0 mg L-1 for flocculation
tests using polyDADMAC alone, while in the hybrid system, PAM dosages in the
range of 0.4 - 8.0 mg L-1. The effectiveness of the flocculation was measured based
on the reduction of the turbidity, the total suspended solids (TSSs), chemical on
demand (COD) reduction and zeta potential measurements. It was found that the
flocculation performance of higher molecular weight samples was more efficient
compared with that of lower molecular weights. This might be due to the bridging
mechanism, which occurred concurrently with the charge neutralization effect during
flocculation. Increasing dosages of polyDADMAC increased the destabilization of
particles and produce small flocs while adding and increasing PAM was increased
the size of flocs for a better synergistic flocculation process.
Description
Keywords
Polydadmac induced flocculation in treatment , of pulp and paper mills wastewater