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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.

The objective of design optimization of pressure vessels is cost reduction by reducing weight with adequate strength and stiffness. Optimization is the act of obtaining the best result under given circumstances. Conventional design aims at finding acceptability design which merely satisfies the functional and other requirements of the problem. In general, there will be more than one acceptable designs and the purpose of design optimization is to choose the best. In the present work parameters such as thickness of the shell, and dish end, length and radius of the pressure vessel are optimized by making use of ACO has been shown for a Pressure vessel problem with four variables and four design constraints. It is found that the results obtained from ACO are better as its search is for global optimum as against the local optimum in traditional search methods. The results of the ACO have been checked using ANSYS, and it is found to perform satisfactorily.

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The effects of different zinc oxide concentration on morphology, contact angle, surface roughness and rejection towards humic acid in polysulfone membrane were investigated. Flatsheet ultrafiltration membrane were prepared by using polysulfone as based polymer, polyethylene glycol as pore forming agent, zinc oxide as manipulated additive and TAP as compatibilizer. In this study, N, methyl-2-pyrrolidone were used as solvent and water as non solvent. The membrane were prepared via phase inversion method. Results showed that pure water flux was enhanced by the presence of zinc oxide up to 1 wt% and tend to decrease beyond this concentration. The increased pure water flux was attributed to the increase in hydrophilicity and surface roughness of membrane according to contact angle and AFM measurement. The rejection test with humic acid as solute revealed that by increasing zinc oxide concentration, rejection increases up to 98% at 2 wt% of zinc oxide. Therefore polysulfone/zinc oxide in this study can provide potential application for river water treatment which consist high humic acid concentration.