Abstract.This study investigates the effect of additive rice husk silica and Polyethylene glycol (PEG) on the performance of polysulfone (PSf) membrane. The membrane was prepared by phase inversion method using PSf, N-methyl-2-pyrrolidone (NMP) and rice husk silica was added as an additive. The performance of the membrane was analyzed by using distilled water for permeation test and humic acid for rejection test. The result showed that the hydrophilic of PSf/PEG membrane has significantly improved permeation and rejection with addition of rice husk silica. The results showed that the addition of 3% rice husk silica give highest rejection flux at 196.63 L/m²hr with the rejection value 98%.

This study investigates the effect of additive rice husk silica and Polyethylene glycol(PEG) at different concentration on of Polysulfone (Psf) ultrafiltration (UF) membranes. The polymer membranes were prepared by a phase inversion method using Polysulfone (PSf) , N-methyl-2-pyrrolidone (NMP) as a solvent and distilled water as non-solvent. The performances of the membranes were measured in term of pure water flux by using distilled water and solute rejection at different wastewater concentration at 50%, 75% and 87.5%. The results demonstrated that the addition 2% and 3% rice husk silica give the good rejection for membranes but the best rejection was at membranes contains 3% rice husk silica where successfully do rejection of 80.5%. As a conclusion,the range between 2%-3% of rice husk silica gives the ideal composition based on the result of flux permeation and rejection.

Abstract.In the present work, polysulfone (PSf) ultrafiltration membranes were prepared by solution casting. The effects of rice husk silica (RHS) on the surface properties of the PSf/Polyethylene glycol (PEG) membrane were observed and investigated. Characterizations were conducted to determine the membrane cross-section area and RHS distribution. The structure of RHS and morphology of membrane were analyzed by using X-ray diffractometer (XRD) and scanning electron microscope (SEM). XRD pattern showed that the amorphous silica was produced from rice husk ash (RHA). The analysis of SEM indicates that the addition of RHS obviously changed the microstructure of the membrane especially at top layer and sub layer. IntroductionPolysulfone (PSf) membrane has been widely used in fabrication ultrafiltration membrane due its low cost, superior film ability, good mechanical and anti-compaction properties and strong chemical and thermal stabilities [1]. However, the hydrophobic nature of PSf gives major problem in water filtration that is fouling. The fouling mechanism is described as pore blocking, solute aggregation or adsorption phenomena. Membrane fouling is characterized in general as a reduction of permeate flux through membrane, as a result of the increased of flow resistant due to pore blocking, concentration polarization and cake formation. The effect of this fouling mechanism on flux decrease depend of factors such as membrane pore size [2] , solute loading and size distribution [3].Membrane surface modification is one method that can be used to increase hydrophobicity and minimize the fouling problem. The common modification method that used to improve the performance is addition of additive into membrane formulation. The addition of small amount of additive into casting solution can lead to significant changes to the characteristic and performance of membrane [4,5,6]. It is reported that additives can affect the final membrane characteristic either by changing the solvent capacity or by changing phase separation kinetic and thermodynamic mechanism [7,8]. The additive have tendency to enlarge macrovoids formation which then improve the interconnectivity of the pores and resulting in higher porosities in the top layer and sub layer [9]. Furthermore, the addition of additive into solution may contribute to the changeable properties of membrane in term of pore distribution, physical properties and mechanical characteristics [10]. According to previous studies, by using fumed silica as an additive, membrane conductivity and

This study investigates the effect of Sodium Chloride (NaCl) coagulant medium with different concentration to produce Polysulfone (PSf) ultrafiltration (UF) asymmetric membrane. The polymer membrane prepared by a phase inversion method using Polysulfone (PSf) as a base polymer, Polyethylene glycol (PEG) 400MW as copolymer additive, N-methyl-2-pyrrolidone (NMP) as solvent and NaCl coagulant medium with different concentration as nonsolvent. In this work, the concentration of immersion medium for membrane phase immersion process prepared based on different coagulation concentration medium NaCl was modified repeatedly in the range of 1-5%. These membrane performance were analyzed via pure water permeation and solute rejection of humic acid. Based on these results, the membrane immersed in 4% concentration of NaCl coagulant medium showed the highest pure water permeation (235.69 l.m -². h -¹) and solute rejection of humic acid which is up to 98%. IntroductionPhase inversion is one of the most popular and common technique that used for most researchers via immersion precipitation as a way to prepare microfiltration and ultrafiltration asymmetric membrane of polymer [1][2][3][4][5] and ceramic membranes [6][7][8]. According to this technique, a thin film of polymer homogenous dope solution is cast on a suitable substrate such as glass, polyester or polyethylene non-woven fabric, metal, Teflon henceforward immersed in a non-solvent bath where exchange between solvent and non-solvent and the precipitation of polymer take place [7].Nevertheless, this conventional method is not flexible enough to produce all the ideal membrane structure and properties. Thus, modification of basic procedure are commonly required including the addition of certain additive [1][2][3][4][5], introducing advance stride to make enhancement such as evaporation [9] or annealing [10], and coupling chemical reaction with phase separation [11]. Previous studies reported that by modification of polysulfone (PSf) ultrafiltration membrane with changing composition in casting solution or coagulation bath will gives positive implication to morphology and properties of membrane [12,13]. Coagulation bath is one of the methods used to make modification of membrane in term of structure and properties with an addition certain additive such as inorganic salt.

This study investigates the effects of synthetic silica(SiO2)with different weight percentage concentrations on the morphology and performance of the polysulfone (PSf) and polyethelene glycol (PEG) based membrane ultrafiltration (UF). Phase inversion method was used to prepare PSf/PEG ultrafiltration (UF) flatsheet membrane. SiO2 and N-Methyl 2 Pyrrolidone (NMP) were used as an additive and solvent respectively. The fabricated membrane was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and the performances of the membranes were measured in term of pure water flux by using distilled water and solute rejection at different wastewater concentration at 50%, 75% and 87.5%. The result showed that the addition of 2% silica in the dope solution increased the permeation in terms pure water flux and the best rejection with 62 Lm-2 h-1 and 89% (at 87.5 % waste water dilution) respectively