Siti Khadijah Hubadillah

Effect of kaolin particle size and loading on the characteristics of kaolin ceramic support prepared via phase inversion technique

Abstract In this study, low cost ceramic supports were prepared from kaolin via phase inversion technique with two kaolin particle sizes, which are 0.04–0.6 μm (denoted as type A) and 10–15 μm (denoted as type B), at different kaolin contents ranging from 14 to 39 wt.%, sintered at 1200 °C. The effect of kaolin particle sizes as well as kaolin contents on membrane structure, pore size distribution, porosity, mechanical strength, surface roughness and gas permeation of the support were investigated. The support was prepared using kaolin type A induced asymmetric structure by combining macroporous voids and sponge-like structure in the support with pore size of 0.38 μm and 1.05 μm, respectively, and exhibited ideal porosity (27.7%), great mechanical strength (98.9 MPa) and excellent gas permeation. Preliminary study shows that the kaolin ceramic support in this work is potential to gas separation application at lower cost.

A low cost, superhydrophobic and superoleophilic hybrid kaolin-based hollow fibre membrane (KHFM) for efficient adsorption–separation of oil removal from water

Inspired by the lotus leaf surface structure, which possesses a hydrophobicity behaviour, a low cost, high performance superhydrophobic and superoleophilic kaolin hollow fibre membrane (KHFM) was obtained by a simple sol–gel grafted method using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) for oil removal from water. The KHFM was grafted at various grafting times ranging from 1 to 5 coating cycles. Prior to the calcination process at 400 °C, the grafted KHFM was dried in an oven at 100 °C for 1 hour for each grafting coating cycle. The grafting process efficiency was measured by the contact angle of water and hexane. Scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM) were used to study the morphology and surface roughness, respectively, of the grafted KHFM. The oil removal was conducted by using the homogeneous mixture of hexane and water. The highest hydrophobicity and oleophilicity was obtained for the KHFM grafted at 2 coating cycles with a contact angle value equal to 157° and 0°, respectively. In fact, the mechanical strength of KHFM was also improved from 16.21 MPa to 72.33 MPa after grafting. In terms of performance, KHFM grafted for 2 coating cycles obtained an almost 99.9% absorption of oil. Thereby, KHFMs were assembled into a module for a filtration study. A high oil flux of 102 L m−2 h−1 was obtained for superhydrophobic and superoleophilic KHFM with 2 grafting coating cycles of 2, and this result is in agreement with the trend of the adsorption result.

PMRs in Photodegradation of Organic Contaminants: Water and Wastewater Treatment

Abstract This chapter describes the potential of photocatalytic membrane reactors (PMRs) for organic pollutants degradation in water and wastewater treatment. Various organic pollutants such as oils, dyes, phenols, pesticides, etc. have been discussed in terms of the danger and treatment process through PMRs. The recent progress showed that PMRs is a promising method toward the treatment of organic pollutants in water. However, the composition of the permeate in terms of oxidation by-products as the intermediates should be also considered during PMR process.

Silica-Based Hollow Fiber Membrane for Water Treatment

Abstract This chapter describes the application of silica-based hollow fiber membrane for water treatment. There are two types of common hollow fiber membrane for water treatment: polymer and ceramic membrane. A well-known phase inversion method was used to prepare these membranes. Accordingly, silica (SiO2) is a well-known glass forming oxide, which can be microporous, mesoporous, and macroporous material. In membrane technology, SiO2 plays an important role in enhancement of the membrane properties as well as performance. For example, addition of silica in polymer membrane matrix could induce higher hydrophilicity behavior, thus increasing membrane flux. However, in terms of geometry, polymer hollow fiber membrane is rarely studied as it offers some drawback. Alternatively, silica-based ceramic hollow fiber membrane has been successfully fabricated from cheap materials such as clays and waste ashes. This kind of technology offers advantages in water treatment as it could not only be used for separation only, but combined separation-absorption application for water treatment like heavy metal removal. Finally, some case studies in water treatment (i.e., oily wastewater separation) are discussed, with potentialities, drawbacks, and future trends.

A MORPHOLOGICAL STUDY OF NICKEL OXIDE HOLLOW FIBER MEMBRANES: EFFECT OF AIR GAP & SINTERING TEMPERATURE

A systematic study of the air gap effects on morphology and mechanical strength of Nickel Oxide (NiO) hollow fiber membranes has been carried out. The hollow fibers were prepared using the dry-jet wet spinning process using a dope solution containing NiO/N-methyl-2-pyrrolidone (NMP)/Arlacel/Poly(ethylene sulphide) with a weight ratio of 70/22.9/0.1/7. Tap water was used as internal and external coagulants. The cross-sectional structure of precursors hollow fiber membrane was studied by scanning electron microscopy (SEM). The results showed that both inner and outer finger-like voids of the hollow membrane were determined by the air gap distance. Experimental results indicated that an increase in air gap distance, from 100 mm to 200 mm, gave a hollow fiber with a lower mechanical strength and higher percentages of cross section surface area covered by finger-like voids structures. This study also revealed that the air gap introduced an elongation stress because of gravity on the internal or external surfaces of the NiO hollow fibers. A more effective hollow fiber membrane which is in asymmetric structure instead of symmetric structure can be produced by using air gap higher than 200 mm.