Wastewater generated in industrial production processes are often contaminated by hazardous chemicals. Characterization by means of toxicity-directed analysis is useful for identifying which fractions of a waste stream possess the most toxicity. We applied this approach to evaluate toxic components of a polyester manufacturing wastewater. Using the reduction in oxygen uptake rate of activated sludge as an indicator of toxicity, it was determined that increasing the pH from 3 to 11 followed by air stripping significantly reduced the toxicity of the wastewater. Comparative headspace GC/MS analysis of wastewater at different pHs selected a group of Volatile Organic Compounds (VOCs) associated with the observed effect of air stripping at pH 11. Ten of these compounds were identified as alpha,beta unsaturated aldehydes (acrolein (2-propenal) congeners); these compounds are known to be toxic as well as mutagenic. Confirmation that these compounds were a cause of toxicity was achieved by demonstrating that removal of these compounds by air stripping significantly reduced the wastewater mutagenic potency in a Salmonella mutagenicity assay. Formation of these volatile compounds by base catalyzed aldol condensation at pH 11 may account for the effectiveness of air stripping in reducing toxicity. To date there is no record in the literature about the toxicity and presence of acrolein congeners in polyester manufacturing wastewater.
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http://dx.doi.org/10.2166/wst.2010.054 | DOI Listing |
Cornea
January 2025
Department of Ophthalmology, Saitama Medical University, Saitama, Japan.
Purpose: This study aimed to describe a novel technique of direct anterior chamber (AC) air replacement (DACAR) for the management of Descemet stripping automated endothelial keratoplasty (DSAEK) in postvitrectomized eyes and eyes with previous glaucoma surgery.
Methods: DACAR was performed after a corneal donor graft was transplanted through a wound using the pull-through technique. DACAR involves stabilizing the graft with forceps while introducing air into the AC via an infusion cannula to ensure complete air exchange.
GMS Hyg Infect Control
December 2024
Institute of Hygiene and Environmental Medicine, University Medicine Greifswald, Germany.
Introduction: Room air class (RC) Ib may be necessary for surgical procedures in aseptic working areas. The aim of the study was to examine whether a mobile, three-stage sterile ventilation unit (MSVU) can replace a room ventilation system (RVS) with turbulent mixed flow (TMF) in the area of the operating field and on the instrument table from hygienic-microbiological point of view.
Method: During 26 surgeries (varicose vein stripping or treatment of umbilical and inguinal hernias), the microbial load was recorded at 4 measuring points (M1-M4) during regular operations by setting up sedimentation plates and measuring the particle concentration.
Angew Chem Int Ed Engl
January 2025
State Key Laboratory for Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
Site density (SD) and turnover frequency (TOF) are the two fundamental kinetic descriptors that determine the oxygen reduction activity of iron-nitrogen-carbon (Fe-N-C) catalysts that represent the most promising alternatives to precious and scarce platinum. However, it remains a grand challenge to simultaneously optimize these two parameters in a single Fe-N-C catalyst. Here we show that treating a typical Fe-N-C catalyst with ammonium iodine (NHI) vapor via a one-step chemical vapor deposition process not only increases the surface area and porosity of the catalyst (and thus enhanced exposure of active sites) via the etching effect of the in situ released NH, but also regulates the electronic structure of the Fe-N-C moieties by the iodine dopants incorporated into the carbon matrix.
View Article and Find Full Text PDFAnimals (Basel)
December 2024
Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research Polish Academy of Sciences, 10-243 Olsztyn, Poland.
This study compared the quality of northern pike eggs collected using traditional methods (hand stripping) and pneumatic methods (air stripping). The effects of different activation solutions (0.4% NaCl, 0.
View Article and Find Full Text PDFMikrochim Acta
December 2024
Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.
The detection of 4-chloro-2-methylphenoxyacetic acid (CMPA) herbicide is crucial due to the potential health risks linked to exposure through drinking water, air, and food, which may adversely affect liver and kidney functions. To address this environmental concern and promote sustainable agriculture, a sensitive carbon paste sensor incorporating a composite material was developed. The composite sensor is based on porous cobalt-1,4-benzenedicarboxylate metal-organic framework and exfoliated montmorillonite nanolayers (Co-OF/MMt).
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