Effect of operating parameter on membrane distillation performance using kapok fibre for humic acid treatment

There is no doubt that in finding solution to the problem of fresh water scarcity and its high demand. Membrane distillation have been shown to be an effective alternative to replace conventional technologies which found uneconomical. As agricultural waste is abundantly available, kapok fibre has been chosen an alternative solution for synthetic membranes which not environmentally friendly. This study aims to determine the physical properties of raw kapok fibre in the membrane distillation system, to investigate the effect of operating parameters in membrane distillation for humic acid in terms of water permeability and rejection rate, and finally to determine the reusability of kapok fibre in the membrane distillation system. The physical properties of the raw kapok fibre have been determined with respect to morphology, absorption test, and water contact angle method. Then, it followed by investigating the performances of the kapok fibre through membrane distillation process with three different operating parameters. Next, reusability test was conducted through the membrane distillation system for about 20 hours. Characterisation test revealed the linkage structure of kapok fibre, the low increment of moisture content in the raw kapok fibre and the water contact angle exhibits 152.704°. Meanwhile, the first operating parameter used in membrane distillation system, which is the temperature of feed humic solution at 60°C has produced the highest permeate flux of 0.629 kg/m2h followed by 98.753 % of rejection at 40°C. Then, the lowest feed concentration of humic acid solution which 0.1 g/L showed the highest permeate flux of 0.634 kg/m2h followed by 97.47 % rejection rate. The 5 g of kapok fibre shows the highest permeate flux with 0.803 kg/m2h and 35g of kapok fibre shows highest rejection rate which 98.91%. The long-time operation has resulted in a slow decrease of permeate flux from 0.321 kg/hm2 to 0.089 kg/m2h after 20 hours. Therefore, the excellence hydrophobic property of the kapok fibre has successfully created an alternative solution for synthetic membrane studies in the membrane distillation process

Effect of operating parameter on membrane distillation performance using kapok fibre for humic acid treatment

There is no doubt that in finding solution to the problem of fresh water scarcity and its high demand. Membrane distillation have been shown to be an effective alternative to replace conventional technologies which found uneconomical. As agricultural waste is abundantly available, kapok fibre has been chosen an alternative solution for synthetic membranes which not environmentally friendly. This study aims to determine the physical properties of raw kapok fibre in the membrane distillation system, to investigate the effect of operating parameters in membrane distillation for humic acid in terms of water permeability and rejection rate, and finally to determine the reusability of kapok fibre in the membrane distillation system. The physical properties of the raw kapok fibre have been determined with respect to morphology, absorption test, and water contact angle method. Then, it followed by investigating the performances of the kapok fibre through membrane distillation process with three different operating parameters. Next, reusability test was conducted through the membrane distillation system for about 20 hours. Characterisation test revealed the linkage structure of kapok fibre, the low increment of moisture content in the raw kapok fibre and the water contact angle exhibits 152.704°. Meanwhile, the first operating parameter used in membrane distillation system, which is the temperature of feed humic solution at 60°C has produced the highest permeate flux of 0.629 kg/m2h followed by 98.753 % of rejection at 40°C. Then, the lowest feed concentration of humic acid solution which 0.1 g/L showed the highest permeate flux of 0.634 kg/m2h followed by 97.47 % rejection rate. The 5 g of kapok fibre shows the highest permeate flux with 0.803 kg/m2h and 35g of kapok fibre shows highest rejection rate which 98.91%. The long-time operation has resulted in a slow decrease of permeate flux from 0.321 kg/hm2 to 0.089 kg/m2h after 20 hours. Therefore, the excellence hydrophobic property of the kapok fibre has successfully created an alternative solution for synthetic membrane studies in the membrane distillation process

Rheological and thermodynamic behaviour of PSf/ZnO: Effect of zinc oxide

Zinc oxide synthesis normally involve zinc precursor and reduction during the preparation. To improve the dispersion of nanoparticle, the ZnO synthesis is the most promising option since the particles can stabilize in dope solution. However, the process of ZnO synthesis required the addition of polar precursor and reduction agents which are expected to influence the rheological and phase inversion properties of membrane dope solution. It is worth to mention that the rheological properties and phase inversion behaviour of the dope solutions play a critical role in determining the membrane morphology and separation performance. The PSf/ZnO dope solution was prepared via in-situ synthesis using three different precursors and reducing agents. The concentration was varied from 0 wt. %, 1 wt.% and 2 wt.% before dissolving in N-Methyl-2-pyrrolidone (NMP) as it will completely dissolved together. Three different precursors used were Zinc Chloride, Zinc Nitrate and Zinc Acetate while Sodium Borohydride, Hydrazine Hydrate and Urea are three different reduction agents. The thermal stability of the dope solutions was analyzed using cloud test measurement and the rheological properties were measured using viscometer toward the viscosity of the dope solution. Thermodynamic stability analysis denotes that that the hydrazine hydrate has the lowest water percentage for 15 wt.% of PSf which is 3.30 %. Meanwhile, zinc acetate with hydrazine hydrate have the lowest water percentage for 15 wt.% PSf which is 1.59 %. This also shows that the zinc chloride binodal line nearly to the solvent/polymer axis which might resulted on faster demixing rate and miscibility gap become shorter. Urea is nearest to binodal line. Viscosity test results to highest viscosity of urea as reducing agent in dope solution. Moreover, it shows that the PSf/ZnO solution have Newtonian behaviour. As the concentration of Zinc Oxide increases, the viscosity increases at the room temperature