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Assaâd Sila Najwa Mlaik Nadhem Sayari Rafik Balti Ali Bougatef 《Journal of Polymers and the Environment》2014,22(1):78-87
Extraction and depolymerisation of chitin and chitosan from shrimp waste material was carried out using fish proteases aided process. A high deproteinization level (80 %) was recorded with an Enzyme/Substrate ratio of 10 U/mg. The demineralization of shrimp waste was completely achieved within 6 h at room temperature in HCl 1.25 M, and the residual content of calcium in chitin was below 0.01 %. The degree of N-acetylation, calculated from the 13C CP/MAS-NMR spectrum, was 85 %. The chitin obtained was converted to chitosan by N-deacetylation. X-ray diffraction patterns also indicated two characteristics crystalline peaks approximately at 10° and 20° (2θ). Chitosan was then evaluated in the treatment of unhairing effluents from the tanning industry. A result showed that chitosan as a coagulant has good performance in alkaline pH and at concentration of 0.5 g/L. Within these conditions, chitosan could decrease turbidity value, total suspended solids (89 % at 1.5 g/L), biological oxygen demand (33.3 % at 1.5 g/L) and chemical oxygen demand (58.7 % at 1.5 g/L). 相似文献
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The phosphate fertilizer industry produces highly hazardous and acidic wastewaters. This study was undertaken to develop an integrated approach for the treatment of wastewaters from the phosphate industry. Effluent samples were collected from a local phosphate fertilizer producer and were characterized by their high fluoride and phosphate content. First, the samples were pretreated by precipitation of phosphate and fluoride ions using hydrated lime. The resulting low- fluoride and phosphorus effluent was then treated with the enhanced biological phosphorus removal (EBPR) process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two-stage anaerobic/aerobic system operating under continuous flow. Pretreated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate (OLR) from 0.3 to 1.2 g chemical oxygen demand (COD)/L.d. The stable and high removal rates of COD, NH4(+)-N, and PO4(3-)-P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L, and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively. 相似文献
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Photocatalytic degradation of 4-chlorophenol under P-modified TiO2/UV system:Kinetics, intermediates, phytotoxicity and acute toxicity 总被引:1,自引:0,他引:1
A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900℃. Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5500 prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500℃ had an apparent rate constant equal to 0.0075 min-1, which is superior to the performance of a commercial photocatalyst Degussa P25 Kapp = 0.0045 min-1 and of unmodified TiO2 (TP0500) Kapp = 0.0022 min-1. From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone (HQ), benzoquinone (BQ) and (4CC) 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato (Lycopersicon esculentum) whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished 相似文献
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Mlaik N Bouzid J Belbahri L Woodward S Mechichi T 《Environmental science and pollution research international》2012,19(1):226-234
Introduction
The unhairing step, a part of the beamhouse process, is particularly polluting, generating an alkaline wastewater with high concentrations of organic and inorganic matter. The aim of this study was to evaluate the treatment of this industrial wastewater using a combination of biological and microfiltration processes. 相似文献5.
Fuzil Nurul Syazana Othman Nur Hidayati Jamal Nur Ain Shazwani Roslee Ab. Mustapa Ana Najwa Alias Nur Hashimah Dollah ‘Aqilah Him Nik Raikhan Nik Marpani Fauziah 《Journal of Polymers and the Environment》2022,30(2):597-612
Journal of Polymers and the Environment - In this study, the potential of graphene oxide-alginate beads (GO-AB) as an adsorbent for bisphenol A (BPA) removal from aqueous solution was investigated.... 相似文献
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