scholarly journals Preparation and application of silver oxide/sawdust nanocomposite for Chromium(VI) ion removal from aqueous solutions using column system

2017 ◽  
Vol 19 (3) ◽  
pp. 412-422 ◽  

This study describes the removal of Cr (VI) ions from aqueous solutions using silver oxide/sawdust nanocomposite (Ag2O/SD NC) that was prepared using the chemical precipitation method. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques were used for characterization of Ag2O/SD NC. The effect of various parameters such as feed solution pH (2, 6, and 10), influent concentration of Chromium (VI) (25-100 mg/L), flow rate (1-5 mL/min) and bed depth (4-12 cm) on breakthrough curves (BTC) were investigated. Three well-known column adsorption kinetics models including Thomas, Adams-Bohart and Bed Depth Service Time (BDST) models were applied to fitting the column experimental data. Based on Thomas model, the equilibrium adsorption reached 13.41 mg/g when a Cr (VI) polluted solution with influent concentration of 25 mg/L Cr (VI) passed through the column with a flow rate of 2 mL/min. Desorption studies reveal that recovery of uploaded Cr (VI) from the Ag2O/SD NC adsorbent or exhausted column regeneration can readily be achieved using a dilute solution of NaOH (0.01 M) as eluent. This study indicated that the Ag2O/SD NC can be used as an effective, efficient and environmentally friendly adsorbent for the removal of Cr (VI) ions from water resources.

2016 ◽  
Vol 19 (1) ◽  
pp. 7-16 ◽  

<p>In this study, nanocomposite of ceria sawdust (CeO<sub>2</sub>/SD) synthesized by precipitation method was utilized for removal of As (III) ions from aqueous solutions. Study of the process was done in column system. Characterization of the nano sized adsorbent particles was carried out using XRD and SEM techniques. The effects of important parameters, such as the value of initial pH, the flow rate, the influent concentration of arsenic and bed depth were studied in the column system. The Thomas model was applied for treatment of the adsorption data at different flow rate, influent concentration and bed depth. The bed-depth/service time analysis (BDST) model was also applied at different bed depth to predict the breakthrough curves. The two models were found suitable for describing the bio sorption process of the dynamic behavior of the CeO<sub>2</sub>/SD adsorbent in column investigation. Based on Thomas model, the equilibrium adsorption reached 8.28 mg g<sup>−</sup><sup>1</sup> when a As(III) polluted solution with influent concentration of As 10 mg l<sup>-1 </sup>passed through the column with a flow rate of 2 ml min<sup>−</sup><sup>1</sup>. All the results suggested the presented nanocomposite as an efficient and cost effective adsorbent for removal of As (III) ions from aqueous solutions.</p>


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1912
Author(s):  
Huijie Zhu ◽  
Qiang Huang ◽  
Mingyan Shi ◽  
Shuai Fu ◽  
Xiuji Zhang ◽  
...  

The effectiveness of nanoscale zero-valent iron(nZVI) immobilized on activated carbon (nZVI/AC) in removing antimonite (Sb(III)) from simulated contaminated water was investigated with and without a magnetic fix-bed column reactor. The experiments were all conducted in fixed-bed columns. A weak magnetic field (WMF) was proposed to increase the exclusion of paramagnetic Sb(III) ions by nZVI/AC. The Sb(III) adsorption to the nZVI and AC surfaces, as well as the transformation of Sb(III) to Sb(V) by them, were both increased by using a WMF in nZVI/AC. The increased sequestration of Sb(III) by nZVI/AC in the presence of WMF was followed by faster nZVI corrosion and dissolution. Experiments were conducted as a function of the pH of the feed solution (pH 5.0–9.0), liquid flow rate (5–15 mL·min−1), starting Sb(III) concentration (0.5–1.5 mg·L−1), bed height nZVI/AC (10–40 cm), and starting Sb(III) concentration (0.5–1.5 mg·L−1). By analyzing the breakthrough curves generated by different flow rates, different pH values, different inlet Sb(III) concentrations, and different bed heights, the adsorbed amounts, equilibrium nZVI uptakes, and total Sb(III) removal percentage were calculated in relation to effluent volumes. At pH 5.0, the longest nZVI breakthrough time and maximal Sb(III) adsorption were achieved. The findings revealed that the column performed effectively at the lowest flow rate. With increasing bed height, column bed capacity and exhaustion time increased as well. Increasing the Sb(III) initial concentration from 0.5 to 1.5 mg·L−1 resulted in the rise of adsorption bed capacity from 3.45 to 6.33 mg·g−1.


2021 ◽  
Vol 235 (3) ◽  
pp. 281-294
Author(s):  
Abida Kausar ◽  
Haq Nawaz Bhatti ◽  
Munawar Iqbal

Abstract Sugarcane bagasse waste biomass (SBWB) efficacy for the adsorption of Zr(IV) was investigated in batch and column modes. The process variables i.e. pH 1–4 (A), adsorbent dosage 0.0–0.3 g (B), and Zr(IV) ions initial concentration 25–200 mg/L (C) were studied. The experiments were run under central composite design (CCD) and data was analysed by response surface methodology (RSM) methodology. The factor A, B, C, AB interaction and square factor A2, C2 affected the Zr(IV) ions adsorption onto SBWB. The quadratic model fitted well to the adsorption data with high R2 values. The effect of bed height, flow rate and Zr(IV) ions initial concentration was also studied for column mode adsorption and efficiency was evaluated by breakthrough curves as well as Bed Depth Service and Thomas models. Bed height and Zr(IV) ions initial concentration enhanced the adsorption of capacity of Zr(IV) ions, whereas flow rate reduced the column efficiency.


2019 ◽  
Vol 322 (3) ◽  
pp. 1841-1848 ◽  
Author(s):  
Florian Scheiflinger ◽  
Marzieh Habibi ◽  
Elham Zeynolabedini ◽  
Christof Plessl ◽  
Gabriele Wallner

Abstract 10 ionic liquids based on 3 different cations and 5 anions were investigated for radionuclide extraction from aqueous solutions. While uranium and 210Po were extracted with satisfying yields irrespective of the feed solution pH, 234Th, 226Ra and 210Pb extraction yields were rather low. The contact time necessary for near to complete extraction was determined as well as the conditions for successful back-extraction. The loading capacities of the ionic liquids for uranium were very high and depended on the uranyl counter-ion. From the leaching of the ionic liquids into the aqueous phase the predominant extraction mechanisms were derived.


2011 ◽  
Vol 287-290 ◽  
pp. 1620-1625
Author(s):  
Yan Wu ◽  
Zai Fang Deng ◽  
Yang Tao ◽  
Xue Gang Luo

Fixed-bed column studies for the removal of Ag(Ⅰ) and Cr(Ⅲ) from individual aqueous solutions using puffed rice husk were investigated in this work. The experiments were conducted to study the effect of important column parameters such as bed height, feed flow rate and feed initial concentration of solution. It was found that increasing bed depth yielded longer service time while increase in influent concentration and flow rate resulted in faster breakthrough. Bed Depth Service Time (BDST) model was applied to analyze the experimental data and the model parameters were evaluated. Good agreement of the experimental breakthrough curves with the model predictions was observed.


2019 ◽  
Vol 25 (4) ◽  
pp. 383-393
Author(s):  
Abel Adeyi ◽  
Siti Jamil ◽  
Luqman Abdullah ◽  
Thomas Choong ◽  
Mohammad Abdullah ◽  
...  

Thiourea-modified poly(acrylonitrile-co-acrylic acid) (TU-poly(AN-co-AA)) polymeric adsorbent was synthesized and characterized with Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM) and Zetasizer. Adsorptive removal of cationic malachite green (MG) dye from aqueous solution in a continuous TU-poly(AN-coAA) packed-bed column was studied. The influences of solution pH (2-9), inlet MG concentration (25-80 mg/L), bed depth (4-8 cm) and linear flow rate (1.5-5.0 mL/min) were investigated via assessment of the column breakthrough curves. Low pH and short bed depth, high MG concentration and flow rate led to early breakthrough of MG. According to correlation coefficients (R2) and sum of the squares of the errors (SSE) values, Thomas and Yoon-Nelson dynamic models are more suitable to describe the column experimental data compared to the Bohart-Adams model. TU-poly(AN-co-AA) exhibited effective separation of MG from the liquid phase and displayed high adsorption capacities after five regeneration cycles.


2013 ◽  
Vol 68 (10) ◽  
pp. 2158-2163 ◽  
Author(s):  
Shenglong Zhang ◽  
Randi Zhang ◽  
Wei Xiao ◽  
Runping Han

Natural peanut husk (NPH) modified with hexadecyl trimethyl ammonium bromide (CTAB) was used as adsorbent to remove 2,5-dimethoxy-4-chloroaniline (DMCH) from solution in a fixed-bed column. Fourier transform infrared spectroscopy analysis and X-ray fluorescence of NPH and modified peanut husk (MPH) showed that CTAB had been introduced onto the surface of NPH. The effects of flow rate and bed depth on breakthrough curves were studied. The Thomas model and the Yan model were selected to fit the column adsorption data and the results showed that the Yan model was better at predicting the breakthrough curves. The adsorption quantity was up to 6.46 mg/g according to the Yan model. The bed depth service time model was used to calculate the critical bed depth from experimental data and it was directly related to flow rate. As a low-cost adsorbent, MPH is promising for the removal of DMCH from solution.


2014 ◽  
Vol 884-885 ◽  
pp. 16-20
Author(s):  
Hai Ning Liu ◽  
Hui Fang Zhang ◽  
Can Gao ◽  
Xiu Shen Ye ◽  
Zhi Jian Wu

A column sorption study was carried out by using four resins (D113, D001, LS-1000, LS-5000) for the adsorption of alkaline-earth metal ions from aqueous solutions. The breakthrough curve was obtained as a function of feed flow rate, and the total and breakthrough capacity values of the resins were calculated. Four kinetic models: Adams-Bohart, Wolborska and Thomas models were applied to experimental data to predict the breakthrough curves of Na-form resins and to determine the characteristic parameters of the column useful for process design. All models were found suitable for describing the whole or a definite part of the dynamic behavior of the column with respect to flow rate and inlet ion concentration. The results obtained would be helpful for the understanding of the competitive adsorption processes and the recovery or removal of one or more alkaline-earth metal ions from aqueous solutions.


Author(s):  
Ramamoorthy Ramasamy ◽  
Renganathan Sahadevan ◽  
Velan Manikam ◽  
Dharmendira Kumar Mahendradas ◽  
Raajenthiren Muniswamy

Biosorption of Acid Blue 5 dye by the Eichhornia crassipes was investigated in batch and column studies. Batch experiments were conducted to study the effect of initial solution pH and dye concentration. Langmuir and Freundlich sorption models were used to represent the equilibrium data. Experimental breakthrough curves in a column were obtained with bed height (5, 10 and 15 cm), flow rate (20, 25 and 30mL/min) and initial dye concentration (50, 75 and 100 mg/L). An increase in bed height and initial dye concentration favors the dye biosorption, while the minimum flow rate produced maximum dye biosorption. It was observed that the uptake of Acid Blue 5 using a bed height of 15 cm, flow rate of 20 mL/min and initial dye concentration of 100 mg/L was found to be more when compared to all other bed height, flow rate and initial dye concentration studied in the present investigation. The Bed Depth Service Time (BDST) model was used for the evaluation of continuous sorption data.


2015 ◽  
Vol 73 (6) ◽  
pp. 1279-1286 ◽  
Author(s):  
Necla Barlik ◽  
Bülent Keskinler ◽  
M. Muhtar Kocakerim

Anionic functionalized monolithic macro-porous polymers were used for the removal of hexavalent chromium(VI) anions from aqueous solution in column experiments. At a flux of 1.0 cm min and 30 mg Cr(VI) L−1 feed concentration, breakthrough capacity and apparent capacity were 0.066 g Cr(VI) g−1 anionic monolith and 0.144 g Cr(VI) g−1 anionic monolith, respectively. The degree of column utilization was found to lie in the range 41–46%. Two kinetic models, theoretical and Thomas models, were applied to experimental data to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design. The simulation of the whole breakthrough curve was effective with the models. At a flux of 1.0 cm min and 30 mg Cr(VI) L−1 feed concentration, the dispersion coefficient and adsorption equilibrium constant (K) were 3.14 × 10−7 m s−1 and 3,840, respectively. Also, Thomas model parameters k1 (rate constant of adsorption) and qm (equilibrium solid-phase concentration of sorbed solute) were 1.08 × 10−3 L mg−1 min−1 and 0.124 g g−1, respectively. After reaching equilibrium adsorption capacity, the monoliths were regenerated using 1 N HCl and were subsequently re-tested. It was found that the regeneration efficiency reduced from 98% after second usage to 97% after the third usage.


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