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Experimental evaluation of eco-friendly flocculants prepared from date palm rachis

Journal of Environmental Sciences 2010年第10期22卷 1539-1543页

作者： Ramzi Khiari Sonia Dridi-Dhaouadi Chadlia Aguir Mohamed Farouk Mhenni Research Unity of Applied Chemistry & Environment Department of Chemistry

Sodium carboxymethylcellulose （CMCNa） is an anionic water soluble polyelectrolyte widely used in many industrial sectors including food, textiles, papers, adhesives, paints, pharmaceuticals, cosmetics and mineral processing. CMCNa was produced by chemical modification of cellulose, and represents many advantages： natural, renewable, non-toxic and biodegradable. In this study, different kinds of CMCNa, prepared from an agricultural waste date palm rachis, were tested as eco-friendly flocculants for drinking water treatment and their performances as flocculants in turbidity removal enhancement were assessed. The prepared materials were characterized by the degree of substitution （DS） and polymerisation （DP）. The study of the effect of some experimental parameters on the coagulation-flocculation performance, using the prepared materials combined with aluminium sulphate （as coagulant）, showed that the best conditions for turbidity treatment were given for pH 8, coagulant dose 20 mg/L, flocculant concentration of 100 mg/L and stirring velocity （during the flocculation step） of 30 r/min. Under the optimum conditions, the turbidity removal using CMCNa, prepared from raw material, was about 95%. A comparison study between the flocculation performance of a commercial anionic flocculant （A100PWG： polyacrylamide） and that of the prepared CMCNa showed that the performance of the waste-based flocculant with a DS of 1.17 and a DP of 480 was 10% better than that achieved by the commercial one.

关键词： carboxymethylcellulose flocculants date palm rachis flocculation process

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Comparison of three flocculants for heavy cyanobacterial bloom mitigation and subsequent environmental impact

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Journal of Oceanology and Limnology 2022年第5期40卷 1764-1773页

作者： Kaixuan LIU Lei JIANG Jinsheng YANG Shuzhan MA Kaining CHEN Yufeng ZHANG Xiaoli SHI Department of Environmental Science and Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China Jiangsu Collaborative Innovation Center of Regional Modern Agriculture&Environmental Protection Huaiyin Normal UniversityHuaiyin 223001China

Cyanobacteria can accumulate as a heavy biomass on the leeward side of large eutrophic lakes,posing a potential threat to public *** mitigating capacity of three flocculants and their potential impacts on the major environmental features of water and sediments was *** indicate that polyaluminum chloride(PAC)and ferric chloride(FeCl)are efficient flocculants that can rapidly mitigate cyanobacterial blooms with chlorophyll-a concentrations higher tnan 1500 ug/L within 15 *** comparison,cationic starch with chitosan could only treat cyanobacterial blooms in chlorophyll-a concentrations of less than 200μg/*** addition of FeClcaused a decline in the pH value,while dissolved oxygen in the water column dropped to 2 mg/L during cationic starch with chitosan treatment for a high cyanobacterial biomass ***,a combination of flocculants and oxygenators should be considered when treating high-concentration cyanobacterial blooms for emergency ***,the cell lysis of cyanobacteria caused by cationic starch with chitosan can result in an increase in total dissolved phosphorus and total dissolved ***,the high accumlation of nutrients in sediments after the settling of cyanobacteria can cause high internal phosphorus *** increase in the total organic carbon of the sediments can threaten lake restoration achieved by planting submerged macrophytes.

关键词： cyanobacterial bloom emergency control flocculants lake restoration

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Addition of Thiourea Host Monomer to Polymer flocculants to Improve Selectivity of Phosphate Sorption

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Journal of Agricultural Chemistry and Environment 2020年第3期9卷 147-158页

作者： Timothy S. Goebel Kevin J. McInnes Scott A. Senseman Robert J. Lascano Alex M. Cullen Timothy J. Fuhrer Sarah Pickle Netochi O. Adeolokun Todd A. Davis USDA Wind Erosion and Water Conservation Unit Lubbock TX USA Department of Soil and Crop Sciences Texas A & M University College Station TX USA Department of Plant Sciences University of Tennessee Knoxville TN USA Department of Chemistry United States Air Force Academy USAF Academy Colorado Springs CO USA Department of Chemistry Radford University Radford VA USA Department of Chemistry Idaho State University Pocatello ID USA

Inorganic phosphate is a common nutrient that is applied as a fertilizer to both agricultural fields as well as urban settings such as private yards, public parks and other urban landscaping. While phosphate typically binds tightly to soil, movement of phosphate off of application sites can occur through soil erosion. The soil and its bound phosphate can then end up in surface waters such as rivers and lakes. Phosphate found in surface water bodies exists both as bound to the suspended clay as well as that free in solution. Elevated phosphate concentration in surface waters can lead to algal blooms and eutrophication. While the phosphate bound to clay in suspension in surface water bodies can be removed by commercially available polymer flocculants, the phosphate that is free in solution is more challenging as it is usually found in low concentrations and other anionic salts are generally present in higher concentrations. To remove phosphate from contaminated water systems, where other anions exist at higher concentrations, it is favorable to have a method of removal that is selective for phosphate. As a proof of principle, thiourea derivatized polymer flocculants were examined for the selective removal of phosphate in the presence of competing anions. The polymer flocculants exhibited selectivity for phosphate through hydrogen bonding and were effective at removing up to 43% of phosphate from simulated wastewater. Computational studies and 1H NMR were used to investigate the selectivity of the thiourea monomer for phosphate over competing anions such as chloride and sulfate.

关键词： Molecular Recognition Thiourea Polymers flocculants Phosphate

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A critical review on flocculants and flocculation

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Non-Metallic Material Science 2019年第1期1卷 11-21页

作者： Srijita Bharti Department of Chemistry Cambridge Institute of PolytechnicRanchi-835103JharkhandIndia

The article critically reviews the applications of biopolymers in the area of water treatment. A number of biopolymers were reported for their flocculation behavior for treating the wastewater and making it suitable for various industrial as well as agricultural purposes via chemical alteration onto its backbone. Wastewater treatment was followed by flocculation process using standard ‘Jar test protocol’. Minute quantities of dosage were found be ideal to diminish the organic, biological and suspended loads from wastewater sample. The process of flocculation using biopolymers was also found economically suitable compared to other various processes applied in water treatment.

关键词： Biopolymers Graft copolymers Polymeric flocculants Standard 'jar test protocol’ Mechanism of flocculation

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Synthesis and Characterization of Ferrate(VI) Alkali Metal by Electrochemical Method

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Advances in Materials Physics and Chemistry 2013年第1期3卷 83-87页

作者： Abdellatif El Maghraoui Abdeleaziz Zerouale Mustapha Ijjaali Mohamed Sajieddine Laboratoire de Chimie de La matière Condensée (LCMC) Faculté des Sciences et Techniques Université Sidi Mohammed Ben Abdellah Fes Morocco Laboratoire de Physique et Mécanique des Matériaux Faculté des Sciences et Techniques Beni Mellal Université Sultan Moulay Slimane Beni Mellal Morocco

This works aims at preparing at room stable Na2FeO4 and tracking its degradation over time. The synthetic, during this step, was carried out by electrochemical method. The latter was given maximum focus because of its simplicity and the high degree of purity of the resulting product with respect to wet and dry method. This paper reviews the development of the electrochemical method applied to the synthesis of stable at room Na2FeO4, optimizing the parameters impacting the performance of the oxidation of iron(II) in to iron(VI) in alkaline NaOH, saturated at a temperature of 61°C and a current density of 1.4 A/dm2, in order to simplify the synthesis process, to minimize the cost and to improve the production of iron(VI) to meet the growing demand of ferrate(VI) useful for water treatment. The supervision of the degradation of synthesized Na2FeO4 shows its stability over a period of 10 months, which makes storage and transport easier. The phases obtained were characterized by IR spectrometry, X-ray, M?ssbauer, spectroscopy and thermogravimeric analysis.

关键词： Ferrate Bactericidal Oxidant flocculants Coagulant Conductivity Cathode

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