ABSTRACT
The demand for zinc oxide surged during the Covid-19 pandemic as gloves became a necessity in daily life. The washing-off of the zinc oxide used to activate crosslinking in glove latex, generates hazardous zinc-containing wastewater, which is conventionally treated by chemical precipitation using lime and caustic soda. This produces large volumes of hazardous sludge. This study aims to demonstrate removal and recovery of zinc from real wastewater via adsorption-desorption-chemical precipitation approach to produce utilizable secondary zinc oxide. A low-cost palm shell activated carbon was used to adsorb zinc from raw wastewater with 93% efficiency, straightforwardly reducing zinc concentration below 2mg/L (discharge standard) within 45min, at pH 7 and 60 °C. Subsequent desorption with 0.3M HCl facilitated recovery of 63% of secondary zinc oxide from the desorption solutions via chemical precipitation and calcination path. Morphological analysis of the synthesized secondary zinc oxide confirmed high crystallinity of hexagonal wurtzite crystalline structure of typical spherical and nanorods particle shapes measuring 102nm in size. Surface area comprised of considerable 59.02 m2/g, with pores volume and size of 0.1735 m3/g and 11.76nm, respectively. This study demonstrated successful recovery of zinc ions from raw industrial wastewater to produce good quality secondary zinc oxide, creating opportunities for zinc recycling, reduction in consumption of chemicals and chemical sludge volume, steering way towards sustainable practices in rubber gloves manufacturing sector.
ABSTRACT
Since the COVID-19 outbreak in late 2019, a surprisingly large amount of personal protective equipment, such as medical rubber gloves, have been frequently used, and this medical waste can cause very major environmental problems. A multidisciplinary collaborative approach is needed to combat the pandemic and lessen the environmental risks associated with the disposal of medical waste. This study developed an innovative approach by incorporating shredded rubber glove fibers (RGF) into aggregates to enhance the fatigue resistance of concrete. In this study, different volume contents (0.5%, 1.0%, 1.5%, 2.0%) of RGF were added to the aggregate for the first time. The effects of different RGF contents on the fatigue characteristics of concrete were examined through repeated loading tests and SEM analysis. The results show that the width and number of cracks produced by rubber glove fiber concrete (RGFC) after repeated loading are significantly reduced compared with normal concrete (NC). Following repeated loading, RGFC exhibited higher total, plastic, and elastic strain values than NC, demonstrating greater deformability and elasticity. However, the maximum total strain growth rate and the total strain growth range of the RGFC group were only 2.26 × 10−3/time and 14.0%, which were significantly smaller than the 3.8 × 10−3/time and 31.7% of the NC group, showing better stability, corresponding to enhance the fatigue resistance of concrete. The interfacial transition zone (ITZ) was abnormally smooth with a thin thickness and no visible gaps were discovered, based on the results of SEM test performed on the RGFC. The findings obtained in this study may provide new ideas for the resource utilization of medical waste. © 2023
ABSTRACT
Since the COVID-19 outbreak in late 2019, a surprisingly large amount of personal protective equipment, such as medical rubber gloves, have been frequently used, and this medical waste can cause very major environmental problems. A multidisciplinary collaborative approach is needed to combat the pandemic and lessen the environmental risks associated with the disposal of medical waste. This study developed an innovative approach by incorporating shredded rubber glove fibers (RGF) into aggregates to enhance the fatigue resistance of concrete. In this study, different volume contents (0.5%, 1.0%, 1.5%, 2.0%) of RGF were added to the aggregate for the first time. The effects of different RGF contents on the fatigue characteristics of concrete were examined through repeated loading tests and SEM analysis. The results show that the width and number of cracks produced by rubber glove fiber concrete (RGFC) after repeated loading are significantly reduced compared with normal concrete (NC). Following repeated loading, RGFC exhibited higher total, plastic, and elastic strain values than NC, demonstrating greater deformability and elasticity. However, the maximum total strain growth rate and the total strain growth range of the RGFC group were only 2.26×10-3/time and 14.0%, which were significantly smaller than the 3.8×10-3/time and 31.7% of the NC group, showing better stability, corresponding to enhance the fatigue resistance of concrete. The interfacial transition zone (ITZ) was abnormally smooth with a thin thickness and no visible gaps were discovered, based on the results of SEM test performed on the RGFC. The findings obtained in this study may provide new ideas for the resource utilization of medical waste.
ABSTRACT
The glove manufacturing industry has seen tremendous growth recently, spurred on by the COVID-19 pandemic. A long-standing shortage of supply of disposable medical gloves has highlighted an urgent need to increase production capacity. This requires glove manufacturers to be quick in adopting best practices, in line with Industry 4.0, in order to optimize various aspects of the industry. Unfortunately, information available in the existing literature is, however, limited due to the confidential nature of the majority of research in this area. This article discusses some opportunities and challenges related to this important chemical industry, from the perspective of control engineering. These insights can point to some interesting directions of future work. Copyright (C) 2022 The Authors.