Studies on the Treatment of Wastewaters Containing Cr6+ with Iron Oxide-Silica Composite Materials Prepared by Different Methods

2014 ◽  
Vol 353 ◽  
pp. 33-38
Author(s):  
Rafique Ullah ◽  
Biplob Kumer Deb ◽  
Mohammad Yousuf Ali Mollah

Chromium (VI) is known to be carcinogenic to humans and thus it is important to ensure the removal of Chromium (VI) from aqueous solutions and industrial effluents. The present study introduces a good alternative method for Cr (VI) removal from aqueous solutions at ambient temperature by adsorption, allowing the development of newer, lower operational cost, and more efficient technology than other processes already in use. Adsorption was found to be dependent on pH and initial concentration of Cr (VI) solution. Results of adsorption studies suggest that pristine iron oxide and silicon (IV) oxide removes 72.10% and 24.73%, respectively. The iron oxide – silicon (IV) oxide composite, prepared in this work, removes 93.88% Cr (VI) in 20 minutes from aqueous solution at an initial concentration of 50 mgL-1at pH 4.8 ± 0.2. The effect of concentration, contact time, adsorbent dose and solution pH on the adsorption of Cr (VI) were studied in detail in batch experiments. Studies of the sorption kinetics shows that equilibrium adsorption was attained in 20 minutes depending on other experimental conditions. The kinetic data justified Lagergren’s first-order kinetic equation. Adsorption isotherm study showed that the results fulfilled the Langmuir Model of adsorption isotherm. The maximum adsorption (98.28%) was recorded at pH 3 in 90 minutes for the initial Cr (VI) concentration of 50 mg L-1. Therefore, it can be concluded that iron oxide – silicon (IV) oxide composite is a potential adsorbent for adsorption of Cr (VI) from aqueous solution.

2020 ◽  
Vol 10 (9) ◽  
Author(s):  
Ramasubbu DhanaRamalakshmi ◽  
Mahalingam Murugan ◽  
Vincent Jeyabal

Abstract The present manuscript reports the removal of arsenic from aqueous solution using iron oxide composite of carbon derived from the plant material Prosopis spicigera L. wood which depletes the ground water of ponds, lakes and other water bodies. The adsorbent was characterised by Fourier Transform Infra Red spectroscopy and Scanning Electron Microscope for surface analysis; Brunauer–Emmett–Teller and methylene blue method for surface area determination and pHzpc for surface charge determination. Experimental conditions such as pH, contact time, adsorbate initial concentration and in the presence other ions are varied to study the batch adsorption equilibrium experiment. The adsorption process was tested with Langmuir and Freundlich isotherm model and Langmuir isotherm was best suited. Sorption kinetics was analysed with pseudo-first- and second-order kinetics but adsorption follows second order kinetics. For an initial concentration of 60 mg/L of As(III) ions, adsorption capacity was found to be 83.84 mg/g at pH = 6.0. Thermodynamically the adsorption process is spontaneous, feasible and endothermic in nature. Adsorption involves pore diffusion, external mass transfer and complex formation. Column study was performed to apply this process for large scale treatment.


2014 ◽  
Vol 1051 ◽  
pp. 583-587
Author(s):  
Ling Tao ◽  
Xiao Wei Song ◽  
Jian Li Yuan ◽  
Jun Ren ◽  
Yan Zhuo Zhang

Adsorption of Cr6+ onto purified attapulgite was investigated with respect to temperature, initial concentration and contact time. The kinetics data related to the adsorption of chromium from aqueous solutions are in good agreement with the pseudo-second order equation in ranges of initial concentration of 20~200 mg/L, and temperature of 298~328K. The thermodynamic experiment results show that the equilibrium adsorption isotherm was closely fitted with the Langmuir model.


2011 ◽  
Vol 197-198 ◽  
pp. 131-135
Author(s):  
Li Fang Zhang ◽  
Ying Ying Chen ◽  
Wen Jie Zhang

Biosorption of chromium (VI) ions from aqueous solution with fungal biomass Penicillium sp. was investigated in the batch system. The influence of contact time, solution pH, biosorbent concentration, initial concentration of Cr (VI) ions and temperature on biosorption capacity of Cr (VI) ions was studied. The uptake of Cr (VI) was highly pH dependent and the optimum pH for biosorption of Cr (VI) ions was found to be 2.0. Biosorption capacity of Cr (VI) ions decreased with increased biosorbent concentration and increased with increase in initial concentration of Cr (VI) ions. The experiment results also showed that high temperatures increased the biosorption capacity of Cr (VI) by fungal biomass. It was found that the biosorption equilibrium data were fitted very well to the kangmuir as well as to the Freundlich adsorption model. The maximum sorptive capacities obtained from the Langmuir equation at temperature of 20, 30 and 40°C were 25.91, 32.68 and 35.97 mg/g for Cr (VI) ions, respectively. The results of this study indicated that the fungal biomass of Penicillium sp. is a promising biosorbent for removal of chromium (VI) ions from the water.


2013 ◽  
Vol 726-731 ◽  
pp. 2100-2106 ◽  
Author(s):  
Hua Zhang ◽  
Xue Hong Zhang ◽  
Yi Nian Zhu ◽  
Shou Rui Yuan

Activated carbon prepared from grapefruit peel, an agricultural solid waste by-product, has been used for the adsorption of Cr(VI) from aqueous solution. The effects of adsorbent dosage, pH and temperature on adsorption of Cr(VI) were investigated. The maximum adsorption yield was obtained at the initial pH of 3. The dynamical data fit very well with the pseudo-second-order kinetic model and the calculated adsorption capacities (23.98, 24.33 and 24.81 mg/g) were in good agreement with experiment results at 20°C, 30°C and 40 °C for the 100 mg/L Cr(VI) solution. The Freundlich model (R2 values were 0.9198-0.9871) fitted adsorption data better than the Langmuir model. The calculated parameters confirmed the favorable adsorption of Cr(VI) on the activated carbon prepared from grapefruit peel.


2012 ◽  
Vol 27 ◽  
pp. 11-18
Author(s):  
Timi Tarawou ◽  
Michael Horsfall

The adsorption of chromium (VI) ions from aqueous solution was studied using pure and carbonized fluted pumpkin waste biomass (FPWB). The kinetic data shows a pseudo-first-order mechanism with rate constants of 1.26 × 10-2 and 1.933 × 10-2 mg g-1 min-1 for the pure and carbonized FPWB, respectively. While the pseudo-second-order mechanism has rate constants of 0.93 × 10-1 and 1.33 × 10-1 mg g-1 min-1 for the pure and carbonized waste biomass respectively. The pseudo-second order kinetic model was found to be more suitable for describing the experimental data based on the correlation coefficient values (R2) of 0.9975 and 0.9994 obtained for pure waste biomass (PWB) and carbonized waste biomass (CWB), respectively. The results obtained from this study show that PWB and CWB have very high removal capacity for chromium (VI) from aqueous solution over a range of reaction conditions. Thus, fluted pumpkin waste biomass (Telfairia occidentalis Hook F) is a potential sorbent for the treatment of industrial effluents containing chromium (VI) contaminant.DOI: http://dx.doi.org/10.3126/jncs.v27i1.6436 J. Nepal Chem. Soc., Vol. 27, 2011 11-18Uploaded date: 16 July, 2012


2021 ◽  
Vol 52 (1) ◽  
pp. 204-217
Author(s):  
Mohammed & Mohammed-Ridha

This study was aimed to investigate the response surface methodology (RSM) to evaluate the effects of various experimental conditions on the removal of levofloxacin (LVX) from the aqueous solution by means of electrocoagulation (EC) technique with stainless steel electrodes. The EC process was achieved successfully with the efficiency of LVX removal of 90%. The results obtained from the regression analysis, showed that the data of experiential are better fitted to the polynomial model of second-order with the predicted correlation coefficient (pred. R2) of 0.723, adjusted correlation coefficient (Adj. R2) of 0.907 and correlation coefficient values (R2) of 0.952. This shows that the predicted models and experimental values are in good agreement. The results of the kinetic study showed that the second-order kinetic model was in good agreement with the experimental results and suggested that the mechanism of chemisorption controlled the LVX adsorption. The experimental results indicated that the adsorption of LVX on iron hydroxide flocs follows Sips isotherm with the value of the correlation coefficient (R2) of 0.937. Sips isotherm shows that both homogenous and heterogeneous adsorption can occur.


2016 ◽  
Vol 17 (3/4) ◽  
pp. 189
Author(s):  
Jirapat Ananpattarachai ◽  
Pattra Aphaiphak ◽  
Rokarn Ard ong ◽  
Puangrat Kajitvichyanukul ◽  
Yung Tse Hung

2018 ◽  
Vol 9 (3) ◽  
pp. 202-212 ◽  
Author(s):  
Mohammad Nasir Uddin ◽  
Jahangir Alam ◽  
Syeda Rahimon Naher

The adsorption capacity of chromium(III) from synthetic waste water solution by a low cost biomaterial, Jute Stick Powder (JSP)was examined. A series of batch experiments were conducted at different pH values, adsorbent dosage and initial chromium concentration to investigate the effects of these experimental conditions. To analyze the metal adsorption on to the JSP, most common adsorption isotherm models were applied. To study the reaction rate, the kinetic and diffusion models were also applied. The morphological structure and variation of functional groups in the JSP before and after adsorption was examined by scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FT-IR). Maximum chromium removal capacities of JSP was 84.34%with corresponding equilibrium uptake 8.4 mg/g from 50 mg/L of synthetic metal solution in 60 minutes of contact time at pH = 6.0 and 28 °C with continuous stirring at 180 rpm. The percent sorption of the biomass decreased with increasing concentration of metal ion but increased with decreasing pH, increasing contact time and adsorbent doses. Data for this study indicated a good correspondence with both isotherms of Langmuir and Freundlich isotherm. The analysis of kinetic indicated that Chromium was consistent with the second-order kinetic adsorption model. The rate of removal of Cr(III) ions from aqueous solution by JSP was found rapid initially within 5-30 minutes and reached in equilibrium in about 40 minutes. The investigation revealed that JSP, a low cost agricultural byproduct, was a potential adsorbent for removal of heavy metal ions from aqueous solution.


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