Exploring the current state of play for cost-effective water treatment by membranes

This article presents a perspective on the current development and application of membranes for the treatment of water. We examine how membranes contribute to the global challenge of sustainable supply of clean water. The main theme is on desalination and how innovative science and emerging technology is being applied. Thus, we appraise how techniques such as advanced membrane materials, biomimetic membranes, hybrid systems, forward osmosis, and membrane distillation are being used to improve production to meet the increasing global demand for water

Improving the performance of trays solar still by using sand beds and reflectors

In order to maintain access to freshwater resources in water-stressed regions, it is important to improve the performance of solar-powered desalination systems with lower cost units like solar stills (SS). However, the SS produces low productivity especially through the rainy or cloudy days due to the indirect diffused beams. Therefore, the main aim of this study is to increase the yield from brackish/seawater via a solar still operating with renewable energy sources. The water depth was lowered, and thermal storage materials with different sand beds trays solar still (TSS) are used to augment the amount of yield from a SS. The effects of sandy bed height, and sand type (black and yellow) on the performance of TSS were investigated. Also, the effect of internal reflectors on the sand TSS performance was investigated. Experimental results revealed that the sandy layer (storage beds) improves the TSS production. The maximum increase in accumulated production of sandy TSS with internal reflectors was reached at sand beds height of 1 cm and black sand. In this case, the freshwater was heightened by 105 % over CSS

Maternal parenting style and body mass index among 6–12-year-old girls in Saudi Arabia: A pilot study

Background: An increasingly high prevalence of overweight and obesity exists among Saudi children. Parenting style may serve as a potential predictor in overweight and obesity. Aim: This study examines parenting style as a potential predictor relationship in overweight and obesity among Saudi children. Methods A cross-sectional study involving 92 paired girls and mothers was conducted to determine the association between maternal parenting styles and Saudi girls’ BMI. Findings: The results indicated that the most prevalent parenting style was the authoritative. Majority of students have a moderate obesogenic environment. However, it was not significantly correlated with students BMI. Also, parenting styles were not significantly correlated with an obesogenic environment. Conclusions: Factors other than maternal parenting styles such as environmental factors, families’ socioeconomic status, or cultural factors might be stronger contributors to an obesogenic environment. Larger heterogenous studies are warranted to explore children's BMI and parenting styles associations in Saudi Arabia

Fabrication and characterization of modified PVDF hollow fiber membrane coated with hydrophobic surface modifying macromolecules for desalination application

Polymeric membrane distillation (MD) can be used as a desalination application. It is a promising technology owing to mechanical stability, flexibility, and chemical resistance. However, polymeric-based MD needs to improve further due to low flux permeation in rejecting salt from seawater feed. PVDF hollow fiber membrane consisted of the hydrophilic (LSMM) and hydrophobic (BSMM) surface modifying macromolecules was fabricated. LSMM structure is end-capped by OH bonds which show hydrophilic nature while BSMM consists of a hydrophobic CF bond. By determining the appropriate ratio of LSMM and BSSM loading in the PVDF substrate, it could enhance the MD performance. LSMM could improve the hydrophilic nature at the lumen of the PVDF hollow fiber membrane which can promote the water flux permeation. On the other hand, the positioning of BSMM at the shell layer of the PVDF hollow fiber membrane through dip coating could lead to greater vapor transport. The effect of BSMM loading on the hydrophobicity, morphology, average pore size, porosity, thermal, and membrane performance was investigated. The BSMM loading at 1.5 wt% exhibited the highest contact angle value of 118.76°. Meanwhile, SEM images revealed finger-like structures as well as the LSMM and BSMM structures at the inner and outer layers of the modified PVDF membranes, respectively. The hollow fiber coated with 1.5 wt% BSMM offered the highest salt rejection percentage of 99.99%. Meanwhile, 1.0 wt% BSMM coated PVDF/PEG/LSMM membrane showed a maximum flux of 20.74 kg/m2.h. Furthermore, the melting point of the resulting membranes was 161 °C with various BSMM loadings which is the typical condition range for membrane distillation operation. In conclusion, the BSMM coating agent has a huge potential to improve the membrane's hydrophobicity and performance