a b s t r a c tThe objective of this work is to promote carbide lime waste (CLW), rejected in nature to reduce the pathogens in urban wastewater sludge. We have engaged in this research project, which is notably based on an integrative approach to CLW in urban sludge stabilization. Due to their intrinsic physical and chemical properties, CLW showed excellent and attractive results for urban wastewater sludge stabilization of Bordj Bou Arreridj city. The obtained results show that the stabilization of sludge is most efficient with high level of CLW percentage. The best elimination of pathogenic microorganisms and dryness is obtained for a 50% CLW dose for various microorganisms such as fecal D Streptococcus, fecal coliform, total mesophilic flora and sulfate-reducing clostridium bacteria. Therefore, the valuing of CLW efficiency in the laboratory showed that their valorization could be extended to the sludge stabilization field.
A B S T R A C TThis work aims to investigate the catalytic properties of the heteropolyacids (HPAs) within photocatalytic process. Photocatalytic degradation of phenol in aqueous solution was performed using Wells-Dawson HPAs as catalysts under UV-illuminated condition at 254 nm. The effects of various parameters such as, concentration of catalyst, initial pH, and initial phenol concentration on the performance of photocatalytic process have been investigated to obtain the efficient and durable catalysts and determine the better reaction conditions. The kinetics and the efficiency of phenol degradation were determined by various analytical techniques, such as HPLC and TOC. The results show that the photocatalytic degradation efficiency increases with decreasing pH and the optimum pH is 2 for both catalysts. The photodegradation follows pseudo-first-order kinetics with rate constants k = 8.56 × 10 −2 and 9.94 × 10 −2 min −1 for iron-and vanadium-substituted HPAs, respectively.
Abstract. Heteropoly compounds in the solid state are ionic crystals (sometimes amorphous) consisting of large polyanions, cations, water of crystallization, and other molecules. Heteropolyacids (HPAs) have several advantages as catalysts. On the one hand, they have a very strong Brønsted acidity, especially the cobalt and cesium salts; on the other hand they are exhibiting fast reversible multielectron redox transformations under mild conditions. The cobalt and cesium salts of wellsDawson HPAs were synthesized and characterized using elemental analysis and spectroscopic techniques ( 31 P-NMR, FT-IR). The wells-Dawson anions possess the ability to accept or release electrons through an external potential or upon exposure to UV radiation (photochemical reactions). The catalytic tests of these salts were investigated on phenol degradation where the UV photodegradation of acidified aqueous solutions (pH = 2) were studied in a batch photoreactor under ambient temperature and continuous circulation of phenol solution. The results reveal high catalytic activity for two HPAs, the best catalyst is the salt of cesium; where the presence of cesium improves significantly both the photcatalytic activity and the selectivity to oxalic acid.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.