Effect of the modification time of coal with aryldiazonium salts on the performance of cellulose–acetate coal heterogeneous reverse osmosis membranes

Gashi, Salih; Daci, Nexhat; Podvorica, Fetah I.; Thaçi, Bashkim

doi:10.1016/j.desal.2007.12.045

Cited by 10 publications

(14 citation statements)

References 6 publications

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“…The retentate of biosorbent pretreatment was subjected to heterogeneous (cellulose acetate-coal) asymmetric reverse osmosis membranes (batch 317). The reverse osmosis film details and experimental reverse osmosis procedure is described elsewhere [14].…”

Section: Methodsmentioning

confidence: 99%

Reverse Osmosis Removal of Heavy Metals from Wastewater Effluents Using Biowaste Materials Pretreatment

Thaçi¹,

Gashi²

2018

Pol. J. Environ. Stud.

108

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The rapid increase in industrial activities during the last decades has caused severe changes in the environment. This development has led to contamination of water resources with toxic contaminants such as heavy metals nutrient ions and dyes. Mining, mineral processing, and metallurgical operations (electroplating units, alloy manufacturing, etc.) generate a considerable amount of polluted water containing toxic heavy metals, which are almost persistent and non-degradable in nature, and which in turn cause adverse effects in the environment. Therefore, the treatment of these wastewaters becomes necessary before being discharged into the environment and river water streams, respectively. Several conventional methods (e.g., chemical precipitation, coagulation, sedimentation, adsorption, reduction, oxidation, solvent extraction, electrolytic extraction, evaporation, ion exchange, dialysis/electrodialysis, membrane processes, etc.) have been used to achieve effective and rapid removal of these environmental contaminants -particularly metal ions because of their toxic nature and high production cost, and limited or decreasing availability of metal deposits [1][2].However, some of these techniques have constrains on their application, such as the high operating cost, energy-intensive use hazardous chemicals, and Pol. J. Environ. Stud. Vol. 28, No. 1 (2019), 337-341 AbstractThe objective of this paper was to investigate the applicability of using biowaste materials prior to reverse osmosis treatment of water and wastewater effluents. The physico chemical properties of wheat bran, maize cob, and olive waste, and adsorption parameters such as metal concentration, adsorbent dose, contact time, and temperature of Cd(II) onto wheat bran are presented. The optimal parameters achieved in these experiment were used for sorptive removal of metal ions (Pb ) from synthetic aqueous solution as well as from wastewater effluents of the mining flotation process. At short pretreatment time, retentate of sufficient concentration was achieved with above biosorbents for further treatment. It is used as feed for reverse osmosis tests. The high removal efficiency of metal ions from synthetic as well as wastewater samples was obtained with low-pressure heterogeneous asymmetric reverse osmosis membranes almost completely by this process.

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Section: Methodsmentioning

confidence: 99%

Reverse Osmosis Removal of Heavy Metals from Wastewater Effluents Using Biowaste Materials Pretreatment

Thaçi¹,

Gashi²

2018

Pol. J. Environ. Stud.

108

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“…In comparison with previous published studies [6,7], CA membranes modified with coal showed considerably better RO characteristics. Therefore, the interest was focused on selecting methods of modification of coal leading to increase in productivity of RO membranes [8,9]. Carbon materials such as activated carbon, activated carbon from coal, from bituminous coal, etc.…”

Section: Introductionmentioning

confidence: 99%

“…IR spectrum of: a) bare (1) and modified coal with nitric acid of the concentrations 0.5 M (2), 1 M (3) and 2 M (4), b) bare (5) modified coalwith nitric acid (6), sulfuric acid (7) and acetic acid(8) …”

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confidence: 99%

Effect of modified coal through chemical activation process on performance of heterogeneous reverse osmosis membranes

Thaçi

Gashi

Daci

et al. 2015

Environ. Protect. Eng.

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Heterogeneous reverse osmosis (RO) membranes have been prepared from cellulose acetate (CA) and modified coal through chemical activation. Nitric acid of various concentrations, sulfuric and acetic acids used for various time periods have been studied with respect to modification of structure of coal and consequently structure of RO membranes. The effect of these variables on the modification of coal was examined by IR spectroscopy. All membranes prepared in such a way showed improved performance in comparison with standard CA membranes. The volume flux of the best RO membranes at 94% level of solute separation was 3.87×10-2 m 3 /(m 2 •h) at 1.76 MPa using aqueous feed solution 400 mg/dm 3 of sodium chloride. The performance improvement was related to increases of charge of groups of coal particles in the membrane, affecting their rheology and morphology resulting in better membrane productivity. The SEM of some membranes have also been presented. These membranes were tested also with 1:1, 1:2, 2:2 and 1:3 inorganic salt solutions. The agreement between the calculated and experimental data of solute separation for studied solutes was reasonably good.

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“…Therefore, this coal was modified with 4-nitrobenzene diazonium salt in acetonitrile or hydrochloric acid. The membranes from cellulose acetate and coal modification show more productivity in comparison than that non modified coal 17 . The modified coal with 4-nitrobenzene diazonium salt shows encouraging results for preparation of heterogeneous reverse osmosis membranes.…”

Section: Introductionmentioning

confidence: 99%

Membrane and Adsorption Processes for Removing of Organics and Inorganics from Urban Wastewaters

Daci-Ajvazi¹,

Thaçi²,

Daci³

et al. 2016

Orient. J. Chem

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Since in Kosovo there are still no water purification plants and untreated wastewaters are discharged in environment, in this paper we've studied methods for removing of different organic and inorganic pollutants from Kosovo urban wastewaters. For best results we've used two methods, reverse osmosis and adsorption. For reverse osmosis, all samples were pretreated with coagulant (FeSO 4 ) and flocculant (CaO) and then treated with reverse osmosis membranes. For adsorption, we used Kosovo coal ash and bentonite, both natural and low cost adsorbents. The analysis of experimental results shows that removing of organic and inorganic pollutants by reverse osmosis was very effective and removed from 93-98% of organics and almost 100% of heavy metal ions. Efficiency of coal ash in removing organics from natural waters was from 88-95%, while the efficiency of bentonite was 77-88%, while removing of heavy metal ions by coal ash was from 79-100% and by bentonite was from 50-92% respectively.

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Effect of the modification time of coal with aryldiazonium salts on the performance of cellulose–acetate coal heterogeneous reverse osmosis membranes

Cited by 10 publications

References 6 publications

Reverse Osmosis Removal of Heavy Metals from Wastewater Effluents Using Biowaste Materials Pretreatment

Reverse Osmosis Removal of Heavy Metals from Wastewater Effluents Using Biowaste Materials Pretreatment

Effect of modified coal through chemical activation process on performance of heterogeneous reverse osmosis membranes

Membrane and Adsorption Processes for Removing of Organics and Inorganics from Urban Wastewaters

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