Abstract:Chitosan (Cs)-based composites were developed by incorporating silica (Cs–Si), and both silica and hydroxyapatite (Cs–Si–Hap), comparatively tested to sequester hexavalent (Cr(VI)) ions from water. XRD and FT-IR data affirmed the formation of Cs–Si and Cs–Si–Hap composite. Morphological images exhibits homogeneous Cs–Si surface, decorated with SiO2 nanoparticles, while the Cs–Si–Hap surface was non-homogeneous with microstructures, having SiO2 and Hap nanoparticles. Thermal analysis data revealed excellent the… Show more
“…However, the percentage of Cr(VI) removal increased with increasing treatment time due to the obtaining of the required contact time between CNCs’ surface and Cr(VI) for adsorption. Moreover, the increase of the active functional group with increasing adsorbent doses for adsorbing Cr(VI) increased the Cr(VI) removal [ 27 , 48 ]. Meanwhile, the percentage of Cr(VI) removal became negligible over 30 min treatment time because of the saturation of the CNCs’ surface with the adsorbed Cr(VI) [ 13 ].…”
Section: Resultsmentioning
confidence: 99%
“…The increase of Cr(VI) removal with increasing temperature from 28 ± 1 °C to 60 °C increased the kinetic energy, which enhanced the Cr(VI) binding on the surface of the CNCs and therefore increased the Cr(VI) adsorption. Moreover, an increase of the temperature decreased the solution’s viscosity, which substantially increased interaction between CNCs particles and Cr(VI) and therefore increased Cr(VI) adsorption [ 27 , 49 ]. However, the decrease of Cr(VI) removal with increasing temperature over 60 °C was due to the degrading of the CNCs particles, which substantially weakened the intermolecular force of CNCs particles and therefore decreased Cr(VI) binding on the surface of CNCs particles [ 13 , 26 ].…”
Section: Resultsmentioning
confidence: 99%
“…Of these, ion exchange and membrane filtration are viewed as the most effective treatment methods for the removal of Cr(VI) from industrial effluent. However, these processes are not commercially applicable for the removal of Cr(VI) from the industrial effluent due to their high operating cost [ 27 , 28 ]. Conversely, adsorption is a simple, versatile, and commercially viable process for the removal of Cr(VI) from the industrial effluent [ 27 ].…”
Section: Introductionmentioning
confidence: 99%
“…However, these processes are not commercially applicable for the removal of Cr(VI) from the industrial effluent due to their high operating cost [ 27 , 28 ]. Conversely, adsorption is a simple, versatile, and commercially viable process for the removal of Cr(VI) from the industrial effluent [ 27 ]. Over the years, various biobased materials are being used as an adsorbent to remove Cr(VI) from industrial effluent [ 27 , 29 ].…”
Section: Introductionmentioning
confidence: 99%
“…Conversely, adsorption is a simple, versatile, and commercially viable process for the removal of Cr(VI) from the industrial effluent [ 27 ]. Over the years, various biobased materials are being used as an adsorbent to remove Cr(VI) from industrial effluent [ 27 , 29 ]. Studies reported that adsorption using CNCs is considered a promising method for Cr(VI) removal because of its easy handling, high efficiency, high adsorption rate, reusability, and economic feasibility [ 24 , 29 ].…”
In the present study, supercritical carbon dioxide (scCO2) was utilized as a waterless pulping for the isolation of cellulose nanocrystals (CNCs) from waste cotton cloths (WCCs). The isolation of CNCs from the scCO2-treated WCCs’ fiber was carried out using sulphuric acid hydrolysis. The morphological and physicochemical properties analyses showed that the CNCs isolated from the WCCs had a rod-like structure, porous surface, were crystalline, and had a length of 100.03 ± 1.15 nm and a width of 7.92 ± 0.53 nm. Moreover, CNCs isolated from WCCs had a large specific surface area and a negative surface area with uniform nano-size particles. The CNCs isolated from WCCs were utilized as an adsorbent for the hexavalent chromium [Cr(VI)] removal from aqueous solution with varying parameters, such as treatment time, adsorbent doses, pH, and temperature. It was found that the CNCs isolated from the WCCs were a bio-sorbent for the Cr(VI) removal. The maximum Cr(VI) removal was determined to be 96.97% at pH 2, 1.5 g/L of adsorbent doses, the temperature of 60 °C, and the treatment time of 30 min. The adsorption behavior of CNCs for Cr(VI) removal was determined using isothermal, kinetics, and thermodynamics properties analyses. The findings of the present study revealed that CNCs isolated from the WCCs could be utilized as a bio-sorbent for Cr(VI) removal.
“…However, the percentage of Cr(VI) removal increased with increasing treatment time due to the obtaining of the required contact time between CNCs’ surface and Cr(VI) for adsorption. Moreover, the increase of the active functional group with increasing adsorbent doses for adsorbing Cr(VI) increased the Cr(VI) removal [ 27 , 48 ]. Meanwhile, the percentage of Cr(VI) removal became negligible over 30 min treatment time because of the saturation of the CNCs’ surface with the adsorbed Cr(VI) [ 13 ].…”
Section: Resultsmentioning
confidence: 99%
“…The increase of Cr(VI) removal with increasing temperature from 28 ± 1 °C to 60 °C increased the kinetic energy, which enhanced the Cr(VI) binding on the surface of the CNCs and therefore increased the Cr(VI) adsorption. Moreover, an increase of the temperature decreased the solution’s viscosity, which substantially increased interaction between CNCs particles and Cr(VI) and therefore increased Cr(VI) adsorption [ 27 , 49 ]. However, the decrease of Cr(VI) removal with increasing temperature over 60 °C was due to the degrading of the CNCs particles, which substantially weakened the intermolecular force of CNCs particles and therefore decreased Cr(VI) binding on the surface of CNCs particles [ 13 , 26 ].…”
Section: Resultsmentioning
confidence: 99%
“…Of these, ion exchange and membrane filtration are viewed as the most effective treatment methods for the removal of Cr(VI) from industrial effluent. However, these processes are not commercially applicable for the removal of Cr(VI) from the industrial effluent due to their high operating cost [ 27 , 28 ]. Conversely, adsorption is a simple, versatile, and commercially viable process for the removal of Cr(VI) from the industrial effluent [ 27 ].…”
Section: Introductionmentioning
confidence: 99%
“…However, these processes are not commercially applicable for the removal of Cr(VI) from the industrial effluent due to their high operating cost [ 27 , 28 ]. Conversely, adsorption is a simple, versatile, and commercially viable process for the removal of Cr(VI) from the industrial effluent [ 27 ]. Over the years, various biobased materials are being used as an adsorbent to remove Cr(VI) from industrial effluent [ 27 , 29 ].…”
Section: Introductionmentioning
confidence: 99%
“…Conversely, adsorption is a simple, versatile, and commercially viable process for the removal of Cr(VI) from the industrial effluent [ 27 ]. Over the years, various biobased materials are being used as an adsorbent to remove Cr(VI) from industrial effluent [ 27 , 29 ]. Studies reported that adsorption using CNCs is considered a promising method for Cr(VI) removal because of its easy handling, high efficiency, high adsorption rate, reusability, and economic feasibility [ 24 , 29 ].…”
In the present study, supercritical carbon dioxide (scCO2) was utilized as a waterless pulping for the isolation of cellulose nanocrystals (CNCs) from waste cotton cloths (WCCs). The isolation of CNCs from the scCO2-treated WCCs’ fiber was carried out using sulphuric acid hydrolysis. The morphological and physicochemical properties analyses showed that the CNCs isolated from the WCCs had a rod-like structure, porous surface, were crystalline, and had a length of 100.03 ± 1.15 nm and a width of 7.92 ± 0.53 nm. Moreover, CNCs isolated from WCCs had a large specific surface area and a negative surface area with uniform nano-size particles. The CNCs isolated from WCCs were utilized as an adsorbent for the hexavalent chromium [Cr(VI)] removal from aqueous solution with varying parameters, such as treatment time, adsorbent doses, pH, and temperature. It was found that the CNCs isolated from the WCCs were a bio-sorbent for the Cr(VI) removal. The maximum Cr(VI) removal was determined to be 96.97% at pH 2, 1.5 g/L of adsorbent doses, the temperature of 60 °C, and the treatment time of 30 min. The adsorption behavior of CNCs for Cr(VI) removal was determined using isothermal, kinetics, and thermodynamics properties analyses. The findings of the present study revealed that CNCs isolated from the WCCs could be utilized as a bio-sorbent for Cr(VI) removal.
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