scholarly journals Arsenic Removal from Aqueous Solutions bySalvadora persicaStem Ash

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ferdos Kord Mostafapour ◽  
Edris Bazrafshan ◽  
Mahdi Farzadkia ◽  
Samira Amini

Arsenic is a naturally occurring metalloid, which is widely distributed in nature and is regarded as the largest mass poisoning in history. In the present study, the adsorption potential ofSalvadora persica(S. persica) stem ash in a batch system for the removal of As(V) from aqueous solutions was investigated. Isotherm studies were carried out to evaluate the effect of contact time (20–240 min), pH (2–11), initial arsenic concentration (50–500 μg/L), and adsorbent dose on sorption efficiency. Maximum removal efficiency of 98.33% and 99.32% was obtained at pH 6, adsorbent dosage 3.5 g/L, initial As(V) concentration 500 μg/L, and contact time 80 and 60 min forS. persicastem ash at 300 °C and 500 °C, respectively. Also, the adsorption equilibriums were analyzed by the Langmuir and Freundlich isotherm models. Such equilibriums showed that the adsorption data was well fitted with the Freundlich isotherm model forS. persicastem ash at both 300 °C and 500 °C (R2=0.8983and 0.9274, resp.). According to achieved results, it was defined thatS. persicastem ash can be used effectively for As(V) removal from the aqueous environment.

Column adsorption of the As (III) & As (V) using rice husk mediated carbon embedded silica (CES) and zeolite (Z-RHA) has been proved promising technique rather than the other conventional methods. The present work investigates the adsorption capability of newly manufactured CES and Z-RHA to remove As (III) & As (V) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray (EDX), and Transmission electron microscopy (TEM) analysis have been investigated for the characterization of synthesized materials. The effects of different parameters like initial concentrations, column diameter, column height, particle size distribution have been investigated. The maximum removal efficiency of CES adsorbents for As (III) is 98% and for As (V) is 85%, and of Z-RHA for As (III) is 95% and for As (V) is 92%. To describe the adsorption behavior the Langmuir and Freundlich isotherm models as well as to kinetics models like Adam-Bohart, Thomas, and Yoon Nelson model were applied. Finally, to dispose of the rice husk mediated adsorbents after arsenic treatment solidification has been done.


2012 ◽  
Vol 610-613 ◽  
pp. 1950-1953
Author(s):  
Zheng Jun Gong ◽  
Wenbo Zhou ◽  
Zhong Ping Qiu

In this study, removal of copper(Ⅱ) from aqueous solutions was examined using corn stalk. In the batch mode adsorption studies, the effects of initial pH and contact time on the copper(Ⅱ) adsorption by the corn stalk have been studied. The results show that: the pH 6.0 and contact time 8 hrs is optimum conditions of this absorption process when the dosage of corn stalk is 0.1g. In the isotherm studies, the Langmuir and Freundlich isotherm models were applied. The R2 of the Langmuir and Freundlich isotherm are 0.981 and 0.944 respectively. The Langmuir adsorption capacity Qmax is 54.05 mg/g. The goodness of fitness was obtained with the Langmuir and Freundlich adsorption isotherms.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
H. Nourmoradi ◽  
Mehdi Khiadani ◽  
M. Nikaeen

Multicomponent adsorption of benzene, toluene, ethylbenzene, and xylene (BTEX) was assessed in aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide (TTAB-Mt). Batch experiments were conducted to determine the influences of parameters including loading rates of surfactant, contact time, pH, adsorbate concentration, and temperature on the adsorption efficiency. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to determine the adsorbent properties. Results showed that the modification of the adsorbent via the surfactant causes structural changes of the adsorbent. It was found that the optimum adsorption condition achieves with the surfactant loading rate of 200% of the cation exchange capacity (CEC) of the adsorbent for a period of 24 h. The sorption of BTEX by TTAB-Mt was in the order ofB<T<E<X. The experimental data were fitted by many kinetic and isotherm models. The results also showed that the pseudo-second-order kinetic model and Freundlich isotherm model could, respectively, be fitted to the experimental data better than other available kinetic and isotherm models. The thermodynamic study indicated that the sorption of BTEX with TTAB-Mt was achieved spontaneously and the adsorption process was endothermic as well as physical in nature. The regeneration results of the adsorbent also showed that the adsorption capacity of adsorbent after one use was 51% to 70% of original TTAB-Mt.


2008 ◽  
Vol 26 (9) ◽  
pp. 693-703 ◽  
Author(s):  
P. Senthil Kumar ◽  
K. Kirthika ◽  
K. Sathish Kumar

The removal of hexavalent chromium, Cr(VI), from aqueous solutions under different conditions using an anion-exchange resin (AXR) as an adsorbent was investigated under batch conditions. Such studies indicated that the percentage adsorption decreased with increasing initial Cr(VI) concentration, with the maximum removal of such ions occurred at a pH value of ca. 2.0. Both the Langmuir and Freundlich isotherm models were capable of reproducing the isotherms obtained experimentally. The sorption process was rapid during the first 20 min with equilibrium being attained within 30 min. The process followed first-order kinetics. The results demonstrate that such anion-exchange resins can be used for the efficient removal of Cr(VI) ions from water and wastewater.


2018 ◽  
Vol 78 (4) ◽  
pp. 827-836 ◽  
Author(s):  
Aysun Bulut ◽  
Sabriye Yusan ◽  
Sule Aytas ◽  
Senol Sert

Abstract This study aimed to investigate and explore the possibility of using ground sea shell powder (Donax trunculus) (SSP) for sorption of Sr(II) ions from aqueous solutions. The maximum removal of Sr(II) removal in SSP was 60% at initial Sr(II) concentration of 25 mg/L, at pH 6.0, contact time 120 min, temperature 25 °C and volume/mass ratio equivalent to 500. Sorption data were interpreted considering the adsorption isotherms and thermodynamic parameters calculated. The maximum Sr(II) adsorption on SSP was 25.45 mg/g at pH 6.0. Freundlich isotherm and Dubinin–Radushkevich models were seen to be more compatible with the sorption equilibrium. The nature of the process was spontaneous and exothermic. The results suggest that SSP could be used as an efficient and cost-effective adsorbent to remove strontium ion.


2018 ◽  
Vol 67 (3) ◽  
pp. 279-290 ◽  
Author(s):  
Haider M. Zwain ◽  
Mohammadtaghi Vakili ◽  
Irvan Dahlan

Abstract A novel RHA/PFA/CFA composite adsorbent was synthesized from rice husk ash (RHA), palm oil fuel ash (PFA), and coal fly ash (CFA) by modified sol-gel method. Effect of different parameters such as adsorbent dosage, contact time, and pH were studied using batch experiment to optimize the maximum zinc (Zn2+) and nickel (Ni2) adsorption conditions. Results showed that the maximum adsorption condition occurred at adsorbent amount of 10 g/L, contact time of 60 min, and pH 7. At this condition, the removal efficiencies were 81% and 61% for Zn2+ and Ni2+, in which the adsorption capacities (qmax) were 21.74 mg/g and 17.85 mg/g, respectively. Adsorption behavior of RHA/PFA/CFA composite adsorbent was studied through the various isotherm models at different adsorbent amounts. The results indicated that the Freundlich isotherm model gave an excellent agreement with the experimental conditions. Based on the results obtained from the kinetic studies, pseudo-second-order was suitable for the adsorption of Ni2+ and Zn2+, compared to the pseudo-first-order model. The results presented in this study showed that RHA/PFA/CFA composite adsorbent successfully adsorbed Zn2+ and Ni2.


2018 ◽  
Vol 34 (5) ◽  
pp. 2548-2553 ◽  
Author(s):  
Naveen Chandra Joshi ◽  
Ajay Singh ◽  
Himanshu Rajput

In the present study, we have used the waste leaves of Myrica esculenta for the removal of Pb2+, Cd2+ and Zn2+ ions from the synthetically prepared waste water. The adsorption based removal process has been carried out under the batch system. The batch system was included pH, contact time, dosage, concentration and temperature. The maximum removal efficiency was achieved at optimized conditions i.e. higher contact time, higher pH, lower metal ion concentrations and moderate temperatures. The presence of various organic binding groups was characterized by FTIR spectroscopy. The percentage adsorption of Pb2+, Cd2+ and Zn2+ ions was found 97.02%, 92.52% and 81.99% at pH 6 after contact time 25 minutes. The data of adsorption were tested with Langmuir, Freundlich and Temkin isotherm models. The adsorption capacity of Pb2+, Cd2+ and Zn2+ ions was evaluated as 8.264, 5.617 and 7.751mgg-1 by Langmuir isotherm model.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
I. Osasona ◽  
O. O. Ajayi ◽  
A. O. Adebayo

The feasibility of using powdered cow hooves (CH) for removing Ni2+ from aqueous solution was investigated through batch studies. The study was conducted to determine the effect of pH, adsorbent dosage, contact time, adsorbent particle size, and temperature on the adsorption capacity of CH. Equilibrium studies were conducted using initial concentration of Ni2+ ranging from 15 to 100 mgL−1 at 208, 308, and 318 K, respectively. The results of our investigation at room temperature indicated that maximum adsorption of Ni2+ occurred at pH 7 and contact time of 20 minutes. The thermodynamics of the adsorption of Ni2+ onto CH showed that the process was spontaneous and endothermic. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were used to quantitatively analysed the equilibrium data. The equilibrium data were best fitted by Freundlich isotherm model, while the adsorption kinetics was well described by pseudo-second-order kinetic equation. The mean adsorption energy obtained from the D-R isotherm revealed that the adsorption process was dominated by physical adsorption. Powdered cow hooves could be utilized as a low-cost adsorbent at room temperature under the conditions of pH 7 and a contact time of 20 minutes for the removal of Ni(II) from aqueous solution.


2011 ◽  
Vol 322 ◽  
pp. 102-107
Author(s):  
Lu Hua You ◽  
Xin Tan ◽  
Qiong Qiong Liu ◽  
Lin Zhao

This article investigates the removal of ammonium from aqueous solutions using the ammonium ion-exchange material prepared by the modified kaolin. Batch tests were performed under a range of conditions to assess the effect of initial solution concentration, contact time and solution PH on the performance and capacity of the media for this application. The findings show that increasing initial solution concentration and contact time provide the best performance at an optimum PH of between 6 and 7 and the maximum ammonium adsorption capacity reaches at 79mgNH4+g-1 under the experimental conditions studied. Five isotherm models were used to describe the isotherm data. Three-parameter isotherm models (Redlich–Peterson and Langmuir–Freundlich) prove a better fit than two-parameter isotherm models (Langmuir, Freundlich and Temkin). These results indicate that the ammonium ion-exchange material is a promising material for cost-effective removal of ammonium from wastewater.


2014 ◽  
Vol 1616 ◽  
Author(s):  
E. Ramos-Ramírez ◽  
N. L. Gutiérrez-Ortega ◽  
G. Rangel-Porras ◽  
G. Herrera-Pérez

ABSTRACTArsenic is one of the most toxic elements that can be found. Arsenic is mainly emitted by the copper, lead and zinc production, in agriculture as pesticides and herbicides. Two forms of arsenic are common in natural waters: arsenite (AsO33−) and arseniate (AsO43−), referred to as As(III) and As(V). The nano-Mg/Al-hydrotalcites present ionic exchange and adsorbent capacities. In this work, the physic-chemical characterization of nano-Mg/Al-hydrotalcites and his arsenic removal capacityis described. The solids were synthesized by the sol-gel method with Mg/Al=2 and 3 ratio. The solids and their thermal treated products were characterized by XRD, FTIR, DTA, TGA and N2 adsorption. The solids were used as adsorbents As(III) in aqueous solutions. Adsorption isotherm studies of As(III) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin–Radushkevich adsorption isotherm models. The As(III) adsorption isotherm data fit best to the isotherm Freundlich model. The maximum As(III) uptake capacity by nano-Mg/Al-hydrotalcites and the heated solids were determined using the Freundlich equation and were found to 547.46, 660.15, 799.88 and 739.12 mg As(III)/g HT-Mg/Al=2, HT-Mg/Al=3, HT-Mg/Al=2 at 350°C and HT-Mg/Al=3 at 350°C respectively. In the kinetic studies using 40 mg/L concentration of As(III) solutions was obtained an excellent removal capacity in contact times less at one minute.


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