This study describes preparation, characterization and examines flocculation characteristic of novel magnesium salt polydiallyldimethylammonium chloride (polyDADMAC) composite flocculants. Five different compositions have been prepared by physical blending between synthesized polyDADMAC and magnesium salt. Fourier transform infrared spectroscopy (FTIR) , intrinsic viscosity and zeta potential measurement were conducted to characterize the properties of the composite flocculants produced. Meanwhile jar test and photometric dispersion analyzer (PDA) were carried out to correlate the flocculation behavior and flocs aggregation. Intrinsic viscosity and zeta potential of composite flocculants increase with increasing of polyDADMAC composition. Composite flocculants (sample B and C) shows better turbidity removal compared to polyDADMAC alone. In this system, magnesium salt acts as a secondary Organic Content (TOC) and also reduced the degree of light absorbance in water caused by the presence of suspended solids. Moreover, the price is low which is in the range of RM 0.30 to RM 0.40 per kilogram. This will contribute reduction of price since synthetic organic polymeric flocculants are expensive.PolyDADMAC is widely use in wastewater treatment, since it is very effective in flocculating, discoloring, and removing organics such as humus and algae 6, 7 .PolyDADMAC is a high-charge-density cationic polymer 8 , which makes it well-suited for the flocculation process. Moreover, it is pH-insensitive as well as chlorine-resistant.Thus, polyDADMAC has been chosen as one of the components for the hybrid composite flocculants used in this study. However the price is quite expensive which it is in the range of RM 3.99 to RM 5.44 per liter.Composite flocculants have been emerged as it poses better performance compared to conventional flocculants 9 . It is believed the performance depends on the aggregating power of composite among inorganic-and organic-based flocculants 10 .Since the magnesium salt and polyDADMAC is considered as a new composite flocculants, thus, a particular emphasis was given to the flocculation mechanism and kinetics. The kinetics were examined by online photometric dispersion analyzer since PDA offers a symptom of changes in aggregation (flocculation) or disaggregation (dispersion, de-flocculation) 11 . This feeding process was carried out for 300 min. The reaction temperature was held at 80 to 85 °C, while the reaction mixture was stirred at 110 to 130 rpm for 10 min.Next, an aqueous solution containing 0.30 g of MBS was prepared in 5 ml of deionized water. The aqueous solution was fed into the reactor dropwise via a syringe pump at 0.1 mL min -1 . The reaction mixture was then cooled to room temperature for 15 h and stored in an airtight container. The whole experiment was conducted at pH of 7 to 9. Thus, in order to keep the crosslinking reaction at a desired pH during the course of the additional initiator feed, NaOH solution was added to the polymerization mixture. Preparation of magnesium salt-polyDADMAC...

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The application of pour point depressants in the form of emulsions provides an alternative to overcoming the problem of handling during applications in cold climate environments. The incorporation of antifreeze agents to these emulsions helps to improve their cold flow properties, without sacrificing much of the other properties. This study considered the effect of the incorporation of different antifreeze agents into ethylene vinyl acetate emulsions that are used as pour point depressants. The results obtained revealed that the ethylene glycol (EG) emulsion system gave the lowest freezing temperature of −45°C, while the propylene glycol emulsion system provided the lowest vitrification temperature of −64°C. The size of the particles in the emulsion was significantly reduced from 359.1 nm to 207.4 to 216.4 nm when an antifreeze agent was used in the emulsion compared to the control sample (pure water). As for the selection of the most suitable antifreeze for the emulsion system, the vitrification performance was a factor that was taken into consideration in the decision to select the EG system due to the fact that this system offered an adequate performance in terms of vitrification efficiency at around −59°C, although it was not as excellent as the vitrification efficiency portrayed in the propylene glycol system. However, the EG emulsion system was the most suitable system for the ethylene vinyl acetate emulsion, as it delivered the best protection against freezing and, at the same time, produced a decent particle size distribution. KEYWORDSanti-freeze agent, cold climate, ethylene vinyl acetate, pour point depressant

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