scholarly journals Sorption of chromium (VI) from electroplating rinse water by strong base anion exchanger: equilibrium and kinetic studies

2021 ◽  
Vol 1913 (1) ◽  
pp. 012076
Author(s):  
Prasanna S Koujalagi ◽  
Harish N Revankar ◽  
Raviraj M Kulkarni ◽  
Vijayendra R Gurjar
Keyword(s):  
Anion Exchanger ◽  
Kinetic Studies ◽  
Strong Base ◽  
Chromium Vi ◽  
Rinse Water

Adsorption and ion exchange of some groundwater anion contaminants in an amine modified coconut coir

1997 ◽  
Vol 35 (7) ◽  
pp. 89-95 ◽  
Author(s):  
Aloysius U. Baes ◽  
Tetsuji Okuda ◽  
Wataru Nishijima ◽  
Eiji Shoto ◽  
Mitsumasa Okada
Keyword(s):  
Ion Exchange ◽  
Low Cost ◽  
Exchange Capacity ◽  
Batch Adsorption ◽  
Ion Exchange Capacity ◽  
Strong Base ◽  
Chromium Vi ◽  
Freundlich Equation ◽  
Adsorption Data ◽  
Coconut Coir

The adsorption of nitrate, chromium (VI), arsenic (V) and selenium (VI) anions in an amine modified coconut coir (MCC-AE : with secondary and tertiary amine functionality) were studied to determine the capability of this easily prepared and low-cost material in removing typical groundwater anion contaminants. Batch adsorption-ion exchange experiments were conducted using 200 mg MCC-AE, initially containing chloride as the resident anion, and 50 ml of different anion-containing water of varying concentrations. It is presumed, at this low pH, that only SeO42− remained as a divalent anion, while monovalent species H2AsO4− and HCrO4− predominated in their respective exchanging ion solutions. The adsorption data were fitted using the Freundlich equation and maximum adsorption for each anion was estimated using their respective Freundlich equation constants. MCC-AE exhibited preference for divalent Cr (VI) and Se (VI) anions compared with the Cl− resident ion. Maximum As (V) adsorption was 0.086 mmol/g, while maximum adsorption of Cr (VI), NO3− and Se (VI) anions was 0.327 mmol/g, 0.459 mmol/g, and 0.222 mmol/g, respectively. The ion exchange capacity of MCC-AE is estimated, based on its exchange capacity for nitrate, to be within 0.46 mmol of positive charges per gram. Similar adsorption experiments were conducted for comparison using commercial chloride-form Amberlite IRA-900 strong base (quaternary amine functionality) anion exchanger, with an exchange capacity of 4.2 meq/g. Maximum adsorption of the different ions in IRA-900 was about 3 times higher for NO3−, 9 times higher for Se (VI), 10 times higher for As (V) and 9 times higher for Cr (VI), than that in MCC-AE. Differences in the ion exchange behavior of MCC-AE and IRA-900 were probably due to the different amine functionalities in the two exchangers. The results suggest that MCC-AE may be used as a low-cost alternative adsorbent/ion exchanger for treatment of anion contaminants in groundwater.

Removal of chromium (VI) from aqueous solutions using Diospyros discolor seed activated with nitric acid: isotherm and kinetic studies

2019 ◽  
Vol 79 (6) ◽  
pp. 1214-1221 ◽  
Author(s):  
Dian Arrisujaya ◽  
Nina Ariesta ◽  
Mamay Maslahat
Keyword(s):  
Nitric Acid ◽  
Aqueous Solutions ◽  
Kinetic Studies ◽  
Adsorption Efficiency ◽  
Batch Experiments ◽  
Adsorption Models ◽  
Chromium Vi ◽  
Optimum Ph ◽  
Scanning Electron ◽  
Analyze Data

Diospyros discolor seed activated with nitric acid was investigated for removing Cr(VI) from aqueous solutions. Batch experiments were used to determine the adsorption efficiency, effect of pH, adsorption isotherm, and kinetics. Langmuir and Freundlich adsorption models were used to analyze data of Cr(VI) uptake. Fourier transform infrared spectroscopy was used to investigate the functional groups and surface morphology was checked using a scanning electron microscope, coupled with energy dispersive spectroscopy. The optimum pH in Cr(VI) uptake was 3.5 and the maximum adsorption efficiency reached 100% at 60 min.

scholarly journals Equilibrium and kinetic studies on adsorption of chromium(VI) onto pine-needle-generated activated carbon

2019 ◽  
Vol 1 (12) ◽  
Author(s):  
George M. Ayoub ◽  
Ahmad Damaj ◽  
Houssam El-Rassy ◽  
Mahmoud Al-Hindi ◽  
Ramez M. Zayyat
Keyword(s):  
Activated Carbon ◽  
Kinetic Studies ◽  
Pine Needle ◽  
Chromium Vi

scholarly journals Adsorption of hexavalent chromium ions from aqueous solutions using nano-chitin: kinetic, isotherms and thermodynamic studies

2021 ◽  
Vol 16 (2) ◽  
pp. 436-451
Author(s):  
Meghdad Sheikhi ◽  
Hassan Rezaei
Keyword(s):  
Aqueous Solutions ◽  
Correlation Coefficient ◽  
Hexavalent Chromium ◽  
Contact Time ◽  
New Technology ◽  
Kinetic Studies ◽  
Chromium Vi ◽  
Effects Of Ph ◽  
Pseudo Second Order ◽  
Adsorbent Dose

Abstract Treatment of the industrial wastewater before discharging into aquatic ecosystems using a new technology such as nanotechnology seems necessary. There are different methods for the removal of the heavy metals in the wastewater. In this study, nano-chitin was purchased from the Nano-Novin Polymer Company and used as an adsorbent for the removal of chromium (VI) ions from aqueous solution in a batch system. The effects of pH, temperature, contact time, concentration, and adsorbent dose were investigated. According to the results, the optimum conditions of adsorption occurred at pH = 6, temperature = 25 °C, 60 minutes contact time, and 0.6 g·L−1 adsorbent dose. Investigation of equilibrium isotherms showed that the isotherm fitted the Freundlich model with a correlation coefficient of R2 = 0.9689. The pseudo second-order model with the larger correlation coefficient had a greater fitness against experimental data in the kinetic studies. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy were calculated, which indicated spontaneous, endothermic, and random processes, respectively. Given the good results of this project, nano-chitin can be suggested as a novel adsorbent which is highly capable of adsorbing hexavalent chromium from aqueous solutions.

scholarly journals Biosequestration of chromium (VI) from aqueous medium using carbonaceous adsorbents derived from Eichhornia crassipes

2021 ◽  
Author(s):  
E PARAMESWARI ◽  
R.P. Premalatha ◽  
V. Davamani ◽  
S.Paul Sebastian
Keyword(s):  
Eichhornia Crassipes ◽  
Kinetic Studies ◽  
Solute Concentration ◽  
Second Order ◽  
Solution Ph ◽  
Chromium Vi ◽  
Dimensionless Constant ◽  
Before And After ◽  
Intra Particle Diffusion ◽  
Favorable Conditions

Abstract Utilization of the biochar that are derived from Eichhornia crassipes (water hyacinth) as biosorbent for Cr (VI) adsorption was investigated. The biochar was characterized before and after Cr (VI) adsorption by SEM, FTIR and EDX. The influencing parameters viz., solution pH, solute concentrations, reaction duration, adsorbent dose and size have been examined. The most favorable conditions for Cr (VI) removal were found to be pH = 2.0, adsorbent size = 0.2 mm, adsorbent dosage = 2.5g/100ml, adsorbate/solute concentration = 100mg/L of Cr (VI) at 25ºC at 250 rpm. Rate of adsorption was rapid and equilibrium was reached at 36 hours. The equilibrium relationship between the sorbent and sorbate was determined using the isotherms Langmuir, Freundlich and Temkin models. The Langmuir dimensionless constant (KR) for each of the solute concentration was ranged between 0 and 1, it indicates the favourable adsorption of Cr (VI) onto the adsorbent. Adsorption data was very well explained through Langmuir isotherm where sorption occurs on monolayer with the maximum biosorption capacity of 55.55 mg/g. Adsorption rate and its mechanisms were elucidated through kinetic studies viz., Pseudo first order, second order, elovich and intra particle diffusion models. On comparison with various kinetic models, results fitted excellently with pseudo second order model (R2 = 0.999). It suggests that Cr (VI) adsorption by could be better described by chemisorption which involves sharing of electrons between adsorbents and adsorbate. Hence, the biochar derived from E. crassipes are efficiently used as an ecofriendly biosorbent for the management of Cr (VI) rich waste water.

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