Competitive adsorption of toxic metals on bentonite and use of chitosan as flocculent coagulant to speed up the settling of generated clay suspensions

Ferhat, Mourad; Kadouche, Slimane; Drouiche, Nadjib; Messaoudi, Karima; Messaoudi, Bouzid; Lounici, H.

doi:10.1016/j.chemosphere.2016.08.125

Cited by 52 publications

(16 citation statements)

References 27 publications

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“…Chitin and its cationic derivative chitosan display functional and physicochemical properties that offer a wide range of industrial applications, and potentially solve numerous problems in the environmental, agricultural, cosmetic, and biomedical fields [2,3,4,5]. In particular, the food applications of chitin and chitosan are numerous, and include food preservation against microbial deterioration due to its antimicrobial activity; the formation of biodegradable films; and the clarification and deacidification of fruit juices, etc.…”

Section: Introductionmentioning

confidence: 99%

Production of Chitin from Penaeus vannamei By-Products to Pilot Plant Scale Using a Combination of Enzymatic and Chemical Processes and Subsequent Optimization of the Chemical Production of Chitosan by Response Surface Methodology

et al. 2017

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The waste generated from shrimp processing contains valuable materials such as protein, carotenoids, and chitin. The present study describes a process at pilot plant scale to recover chitin from the cephalothorax of Penaeus vannamei using mild conditions. The application of a sequential enzymatic–acid–alkaline treatment yields 30% chitin of comparable purity to commercial sources. Effluents from the process are rich in protein and astaxanthin, and represent inputs for further by-product recovery. As a last step, chitin is deacetylated to produce chitosan; the optimal conditions are established by applying a response surface methodology (RSM). Under these conditions, deacetylation reaches 92% as determined by Proton Nuclear Magnetic Resonance (1H-NMR), and the molecular weight (Mw) of chitosan is estimated at 82 KDa by gel permeation chromatography (GPC). Chitin and chitosan microstructures are characterized by Scanning Electron Microscopy (SEM).

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Section: Introductionmentioning

confidence: 99%

Production of Chitin from Penaeus vannamei By-Products to Pilot Plant Scale Using a Combination of Enzymatic and Chemical Processes and Subsequent Optimization of the Chemical Production of Chitosan by Response Surface Methodology

et al. 2017

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“…It can be used as biopesticide in agriculture, fining agent in winemaking, antibacterial agent in medicine and flocculent coagulant in removal of toxic metals etc. (Bouhenna et al, 2015, Ferhat et al, 2016.…”

Section: Primary and Secondary Screening Of Isolates For Degradation mentioning

confidence: 99%

Purification and molecular characterization of chitinases from soil actinomycetes

Das¹,

Kumar²,

Kumar³

et al. 2017

Afr. J. Microbiol. Res.

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Microbial extracellular chitinases are used in agriculture as effective biocontrol agents and in waste degradation, pharmaceutical and food industry. Actinomycetes are widely tapped group for production of extracellular chitinases. In the present study, approximately 260 actinomycetes were isolated from various ecological habitats was subjected to primary analyses and screened for production of chitinase by plate assay method. Diameter of zones of hydrolysis ranged from 8 to 16 mm. Based on the results, isolates 130, 194, 184, NRRLB 24916 (Streptomyces mexicanus) and NRRLB 16746 (Streptomyces albidoflavus, positive control) were selected for secondary screening and purification. Enzyme activity was estimated in crude cell free extract and partially purified samples. Activity ranged from 7.16 to 14.12 IU/ml (in crude extracts) and 12.1 to 23.10 IU/ml (in partially purified samples). In case of highest chitinase producing isolate 130, effect of various fermentation conditions (pH, temperature and substrate concentration) was studied in crude extract. Furthermore, complete purification of isolate 130 was done by column chromatography and the activity in purified fraction was found to be 32.12 IU/ml. The K m and V max values of the purified fractions for isolate 130 were 2.11 µg/ml/min and 53.11mg/ml respectively. This shows that the enzyme has high affinity for the substrate. SDS gel electrophoresis of the purified fraction showed presence of single band of approximately 65 to 70 kDa. Analyses of purified chitinase were done using MS/MS technique. N-terminal sequence corresponded to chitinase, the gene encodes a protein of 453 amino acid residues. Comparison of deduced amino acid sequence to other chitinases in the database indicated that enzyme showed 70% similarity with chitinase from Streptomyces plicatus and belongs to glycoside hydrolase family 18. Homology modeling showed that the enzyme was folded into a domain of (α/β) 8 barrel structure. Identification of secondary structure was done by CD spectroscopy. Isolate 130 was capable of degrading biodegradable wastes such as crustacean shells.

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“…In recent years, a series of researches using environmentally friendly methods for water treatment, such as the removal of algae or eutrophic substances and heavy metals, have been intensively studied [22][23][24][25][26][27][28]. As a few examples, Pan et al demonstrated that the cationic starch using corn achieves effective removal of algal cells by means of charge neutralization [22].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, chitosan modified soil was utilized as a biodegradable reagent to flocculate the algal cell [23]. Furthermore, Ferhat et al proved that heavy metals such as copper and zinc were effectively adsorbed by using a modified clay and chitosan [28]. During our previous research for synthesis of precipitated calcium carbonate (PCC) using the oyster shell [29], our group has considered that waste oyster shell can be an environmentally friendly reagent for removing algae or eutrophic substances.…”

Section: Introductionmentioning

confidence: 99%

Effect by Alkaline Flocculation of Algae and Phosphorous from Water Using a Calcined Waste Oyster Shell

Nam

Choi²,

Lee

et al. 2017

Water

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Alkaline flocculation has been considered as a potential candidate to remove algae and eutrophic substances from water. A number of researches using low-cost and environmentally friendly methods have been suggested to optimize removal efficiency. In this study, a calcium-containing waste oyster shell, as an environmentally friendly substance, has been used to treat phosphorous, a eutrophic substance, and to remove algae from the fresh water simultaneously. The X-ray Fluorescence (XRF) analysis showed that CaO was a major phase in a raw oyster shell, which played an important role for flocculation of phosphorous as well as algae. In order to eliminate the algae or phosphorous effectively, oyster shell was calcined at 1000 • C and hydrated in water. The slurry of hydrated calcined oyster shell, from 5 g/L to 12.5 g/L, was utilized in this experiment, where the experimental results were compared with that of dolomite. A series of experimental investigations, such as pH and turbidity changes using the water quality analyzer and UV-Visible spectroscopy (UV-Vis), demonstrated that the algae were efficiently removed. In addition, total phosphorous (TP) and total nitrogen (TN) analyses at different amounts of slurries of the hydrated calcined oyster shell showed that almost all the phosphorous was removed at 7.5 g/L of hydrated oyster shell, but due to the high solubility of nitrogen compounds, no obvious effect for the removal of nitrogen was observed. Furthermore, powder X-ray diffractions (PXRD) showed that Ca(OH) 2 compounds were transformed to the phosphate compound, suggesting that the oyster shell caused flocculation by chemically forming with phosphorous ions.

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Competitive adsorption of toxic metals on bentonite and use of chitosan as flocculent coagulant to speed up the settling of generated clay suspensions

Cited by 52 publications

References 27 publications

Production of Chitin from Penaeus vannamei By-Products to Pilot Plant Scale Using a Combination of Enzymatic and Chemical Processes and Subsequent Optimization of the Chemical Production of Chitosan by Response Surface Methodology

Production of Chitin from Penaeus vannamei By-Products to Pilot Plant Scale Using a Combination of Enzymatic and Chemical Processes and Subsequent Optimization of the Chemical Production of Chitosan by Response Surface Methodology

Purification and molecular characterization of chitinases from soil actinomycetes

Effect by Alkaline Flocculation of Algae and Phosphorous from Water Using a Calcined Waste Oyster Shell

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