Adsorptive removal of chromium(VI) from aqueous solution unto groundnut shell

Bayuo, Jonas; Pelig-Ba, Kenneth Bayetimani; Abukari, Moses Abdullai

doi:10.1007/s13201-019-0987-8

Cited by 138 publications

(80 citation statements)

References 32 publications

(30 reference statements)

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“…The slow increase at the later stage as reflected by small increase in adsorption capacity was ascribed to low number of unoccupied sites and adsorbate molecules occupy the remaining vacant sites slowly due to repulsive forces between adsorbate molecules of the solid and liquid phases. Similar results have been reported for adsorption of CV dye on sawdust activated carbon [32], MG dye on biochar [33] and Cr(VI) on groundnut shell [34].…”

Section: Effect Of Contact Timesupporting

confidence: 89%

Adsorptive Removal of Basic Dyes and Hexavalent Chromium from Synthetic Industrial Effluent: Adsorbent Screening, Kinetic and Thermodynamic Studies

Yunusa¹,

Usman²,

Ibrahim³

2020

IJEM

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：The feasibility of utilizing an abundant agricultural waste (desert date seed shell) as an alternative lowcost adsorbent for the removal of hazardous basic dyes [crystal violet (CV) and malachite green (MG)] and hexavalent chromium [Cr(VI)] from synthetic industrial effluent was investigated. Five different adsorbents including the raw, carbonized and chemically activated carbons were prepared and screened with respect to adsorption efficiency of the chosen adsorbates. The prepared adsorbents were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and pH of zero point charge (pHzpc) analyses. The effects of operational variables such as solution pH, contact time and temperature on adsorption have been investigated. The removal of the adsorbates was found to be highly pH-dependent and the optimum pH was determined as 8.0 for the dyes and 2.0 for hexavalent chromium. The screening results revealed that the NaOH activated carbon (NAC) has the best adsorption characteristics with removal efficiencies of 91.10, 99.15 and 91.5 % for CV, MG and Cr(VI), respectively. The process dynamics was evaluated by pseudo-first-order and pseudosecond-order kinetic models. Experimental data have been found to be well in line with the pseudo-second-order model, suggesting therefore, a chemically-based sorption process. Negative Gibbs free energy change (∆G) values obtained from thermodynamic analysis indicated that the adsorption process was spontaneous and had a high feasibility. Positive values for enthalpy change (∆H) showed that the removal process was endothermic, implying that the amount of adsorbate adsorbed increased with increasing reaction temperatures. Additionally, positive values of entropy change (∆S) reflect the high affinity of the adsorbent material to the adsorbates. On the basis of results and their analyses, it has been established that adsorbent derived from desert date seed shell has a promising potential in environmental applications such as removing hazardous substances from industrial effluents. Through this work, it is believed that contributions are provided to the scientific investigations about the decontamination of precious water resources.

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Section: Effect Of Contact Timesupporting

confidence: 89%

Adsorptive Removal of Basic Dyes and Hexavalent Chromium from Synthetic Industrial Effluent: Adsorbent Screening, Kinetic and Thermodynamic Studies

Yunusa¹,

Usman²,

Ibrahim³

2020

IJEM

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“…Consequently, the probability of collision between the adsorbate and adsorbent active sites increase and thus leading to higher Cr(VI) uptake [39,40]. These observations are consistent with previous reports [41,42].…”

Section: Influence Of Initial Concentrationsupporting

confidence: 90%

Equilibrium and Thermodynamic Studies on Adsorption of Hexavalent Chromium from Aqueous Solution onto Low Cost Activated Carbon

Yunusa¹,

Ibrahim²

2020

IJEM

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The removal of hexavalent chromium [Cr(VI)] is a challenging task due to its acute toxicity even at low concentration. In the present study, a low-cost activated carbon (LAC) was prepared from desert date seed shell by chemical activation with H 3 PO 4 and utilized for the removal of hexavalent chromium from aqueous solution. Batch experiments were conducted to investigate the influence of operating variables such as pH, contact time, adsorbent dosage, initial concentration, co-existing ions and temperature. The amount of Cr(VI) adsorbed was found to vary with solution pH and maximum adsorption was observed at a pH value of 2.0. The extent of chromium uptake (mg g-1) was found to increase with increase in initial concentration and contact time. The applicability of the four isotherm models for the present equilibrium data follows the sequence: Freundlich > Temkin > Langmuir > Dubinin-Radushkevich. The mean free energy from the Duninin-Radushkevic isotherm model hinted that the adsorption of Cr(VI) onto the adsorbent surface follows physisorption mechanism. Thermodynamic parameters related to adsorption, Gibbs free energy change (∆G°), enthalpy change (∆H°), entropy change (∆S°), were also calculated and the negative value of ∆H° indicates the exothermic nature of the adsorption process. The considerable adsorption capacity of 99.09 mg g-1 is a signifier of the suitability of the prepared adsorbent for commercial application. The findings implicated that the adsorbent can be employed in the treatment of Cr-bearing water and wastewater.

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“…This could be attributed by the saturation of adsorption sites. However, rapid chromium adsorption in the initial stage is due to the high initial Cr(VI) concentration on the adsorbate and the corresponding available vacant sites on the clay mineral adsorbent materials [16,44,45]. The final adsorption capacities of Cr(VI) from aqueous solution using NC and MC600 are 7.0 and 10.0 mg/g, respectively.…”

Section: Chromium Adsorption Related To Contact Timementioning

confidence: 99%

“…However, by increasing the solution pH, the deprotonation mechanism of the active groups is occurred and this attributed to a decrease in the number of positively charged sites on the clay adsorbent. Hence, Cr(VI) adsorption from aqueous solution is preferred due to the increasing of the electrostatic attractive interactions between the clay surface and the chromium ions in the solution [1,44]. However, further increase in the solution pH that results in a reduction in the chromium uptake.…”

Section: 233mentioning

confidence: 99%

Eco-friendly removal of hexavalent chromium from aqueous solution using natural clay mineral: activation and modification effects

Ashour

Tony

2020

SN Appl. Sci.

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Inexpensive and naturally abundant clay mineral is investigated as a non-toxic and environmentally friendly adsorbent. The clay adsorbent prepared from natural clay (NC) by drying and milling then treated with diluted HCl before calcination to 600 °C. The structural and morphological properties of this modified clay are investigated by Fourier-transform infrared spectroscopy and scanning electron microscope. NC and modified clay at 600 °C (MC600) were applied for hexavalent chromium, Cr(VI), removal from aqueous media via batch adsorption facility. According to the experimental results, the adsorption capacity for chromium removal was calculated (14.3 mg g −1) with a removal efficiency reached to 66% after 90 min of equilibrium time. The sorption matrix indicated that Cr(VI) removal is following the pseudo-second order kinetic model. The experimental data are well fitted with Freundlich isotherm model and the adsorption process is suggested to follow a chemisorption and favourable uptake. The clay reusability was also tested and the outcomes suggested that MC600 had good potential as an economic adsorbent for chromium removal from contaminated water. According to this finding, modified NC is an effective adsorbent for direct Cr(VI) removal from aqueous media and the clay material is signified as an efficient treatment technology can also be adapted to heavy metal removal in wastewater treatment applications and could replace the commercially available adsorbents.

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Adsorptive removal of chromium(VI) from aqueous solution unto groundnut shell

Cited by 138 publications

References 32 publications

Adsorptive Removal of Basic Dyes and Hexavalent Chromium from Synthetic Industrial Effluent: Adsorbent Screening, Kinetic and Thermodynamic Studies

Adsorptive Removal of Basic Dyes and Hexavalent Chromium from Synthetic Industrial Effluent: Adsorbent Screening, Kinetic and Thermodynamic Studies

Equilibrium and Thermodynamic Studies on Adsorption of Hexavalent Chromium from Aqueous Solution onto Low Cost Activated Carbon

Eco-friendly removal of hexavalent chromium from aqueous solution using natural clay mineral: activation and modification effects

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