scholarly journals Synthesis and Characterization of a Chemically-Activated Novel Mesoporous Silica for Cobalt Decontamination from Polluted Water

2019 ◽  
Vol 14 (2) ◽  
pp. 276-289 ◽  
Author(s):  
Sina Matavos-Aramyan ◽  
Sadaf Soukhakian

Mesoporous silica was synthesized by a chemical process and its efficiency was investigated for removal of cobalt (Co2+) ions from contaminated water in a laboratory scale. The characteristics of synthesized mesoporous were analyzed by SEM/TGA. Optimal conditions were determined for important parameters such as solution pH, the absorbent dose, the initial Co2+ concentration, and contact time by a single-variable method through the batch experiments. The SEM results confirmed the synthesized silica had high porosity with a honeycomb-like structure. The results showed that with an increasing adsorbent dose and contact time to the optimum, the efficiency of Co2+ adsorption increased. However, with increasing concentration of Co2+, the removal efficiency decreased. At optimal contact time (8 h), 85 % of Co2+ was removed. The maximum adsorption efficiency at pH =7, initial Co2+ concentration of 5 ppm, and at the adsorbent dose 0.3 g/50 ml, was 89%. The study of adsorption isotherm and kinetic models showed that the adsorption process followed the Freundlich isotherm (R2 = 0.9359) and the second-order kinetic model (R2=0.999). Therefore, the synthesized mesoporous silica presented a chemical adsorption mechanism for Co2+ removal from aqueous media and can be utilized in wastewater treatment containing divalent heavy metals such as Co2+.

Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.


2020 ◽  
Author(s):  
Gideon Masedi Nii Ayi Lomoko ◽  
Dainius Paliulis

The purpose of the study underlying the present paper was to determine the adsorption of copper ions which happens to be one of the most important toxic heavy metals in the environment; for that purpose a test was carried out under laboratory conditions using wheat bran as adsorbent. The object of the test was to examine the effect of solution pH, contact time, adsorbent dose and initial copper ions concentration (2 mg/L to 20 mg/L) on adsorption yield and uptake. Three masses of wheat bran (0.5 g, 1.0 g and 2.0 g) were used for this experiment. 1.0 g of wheat bran gave a maximum adsorption efficiency at pH 5.0. At this pH, the adsorption efficiency for initial copper ions concentration of 5 mg/L was found to be 65.8% at room temperature for a contact time of 60 min. The adsorption of copper ions slowly reached equilibrium at 30 mins. With an adsorbent dose of 0.5 g of wheat bran, a maximum uptake of 0.277 mg/g of copper ions was recorded. With increasing mass of adsorbent dose from 0.5 g to 2.0 g. the adsorption uptake of copper ions decreased from 0.273 mg/g to 0.087 mg/g The highest removal efficiency of copper ions was found to be at a metal concentration of 5 mg/L. With the metal concentration increasing the adsorption of copper ions by 0.5 g of wheat bran decreased from 52.0% to 39.9%.


Author(s):  
Nnaemeka John Okorocha ◽  
J. Josphine Okoji ◽  
Charles Osuji

The potential of almond leaves powder, (ALP) for the removal of Crystal violet (CV) and Congo red (CR) dyes from aqueous solution was investigated. The adsorbent (ALP) was characterized by FTIR and SEM analysis. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were studied to observe their effects in the dyes adsorption process. The optimum conditions for the adsorption of CV and CR dyes onto the adsorbent (ALP) was found to be: contact time (100mins), pH (10.0), temperature (343K) for an initial CV dye concentration of 50mg/L using adsorbent dose of 1.0g and contact time (100mins), pH (2.0), temperature (333K) for an initial CR dye concentration of 50mg/L using adsorbent dose 1.0g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for both CV and CR dyes adsorption. The maximum adsorption capacity of ALP was found to be 22.96mg/g and 7.77mg/g for the adsorption of CV and CR dyes respectively. The kinetic data conformed to the pseudo-second-order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were evaluated and the negative values of ΔG0obtained for both dyes indicate the spontaneous nature of the adsorption process while the positive values of ΔH0and ΔS0obtained indicated the endothermic nature and increased randomness during the adsorption process respectively for the adsorption of CV and CR onto ALP. Based on the results obtained such as good adsorption capacity, rapid kinetics, and its low cost, ALP appears to be a promising adsorbent material for the removal of CV and CR dye stuff from aqueous media.


2020 ◽  
Author(s):  
Fola Temilade Akinhanmi ◽  
Edwin Andrew Ofudje ◽  
Idowu Abideen Adeogun ◽  
Aina Peter ◽  
Joseph Mayowa Ilo

Abstract The presence of heavy metals in polluted water is known not only to cause stern harm to marine organisms but also to terrestrial plants and animals including human beings. This research applied low-cost and environmental benign adsorbent primed from waste orange peel (OP) for the removal of Cd(II) ions from aqueous solution via batch adsorption process. The surface properties of the orange peel powder were studied using Scanning Electron Microscopy (SEM), X-ray spectroscopy (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Operational conditions like temperature, contact time, sorbent dosage, solution pH and initial adsorbate concentration were investigated. The utmost uptake of Cd(II) ion was obtained at a contact time of 120 mins, initial metal concentration of 240 mg/L, adsorbent dosage of 0.04 g/L, temperature of 45 °C and solution pH of 5.5. Equilibrium results showed that the orange peel adsorbent has an adsorption capacity of 128.23 mg/g as obtained from the Langmuir isotherm. The adsorption kinetics data followed a pseudo-first-order kinetic model with correlation coefficient (R2) >0.9 and low standard % error values. The adsorption process was found to be endothermic in nature with enthalpy of 0.0046 kJ mol−1 and entropy of-636.865 Jmol-1K-1 respectively. Results from the optimization study indicated that higher adsorbent dosage and lower Cd(II) ion concentration increased the percentage of Cd (II) ion removal. Thus, orange peel could be used in the removal of Cd(II) ion from aqueous solutions.


2012 ◽  
Vol 9 (2) ◽  
pp. 621-630 ◽  
Author(s):  
Farah Kanwal ◽  
Muhammad Imran ◽  
Liviu Mitu ◽  
Zeeshan Rashid ◽  
Huma Razzaq ◽  
...  

This study is concerned with the development of some synthetic polymers, copolymers and their sulfonated derivatives as adsorbents. The effectiveness of these adsorbents in removing Cr(III) from aqueous solution was evaluated by batch technique. The influence of different experimental parameters on removal process such as solution pH, contact time, adsorbent dose, Cr(III) concentration and temperature were evaluated. Adsorption equilibrium was achieved in 20 to 30 min. at pH > 5. The Langmuir, Freundlich and Temkin adsorption isotherms were used to elucidate the observed sorption phenomena. The maximum Cr(III)37.8 mg/gram of PS(polystyrene) and 37.2 mg/g of SAN (styrene/acrylonitrile copolymer) was removed as evaluated from Langmuir isotherm while the heat of sorption was in the range 0.21–7.65 kJ/mol as evaluated from Temkin isotherm. It can be concluded that PS developed in this study exhibited considerable adsorption potential for application in removal of Cr(III) from aqueous media as compared to its copolymers and other derivatives used in this study.


2020 ◽  
Author(s):  
Fola Temilade Akinhanmi ◽  
Edwin Andrew Ofudje ◽  
Idowu Abideen Adeogun ◽  
Aina Peter ◽  
Joseph Mayowa Ilo

Abstract The presence of heavy metals in polluted water is known not only to cause stern harm to marine organisms but also to terrestial plants and animals including human beings. This research applied low-cost and environmental benign adsorbent primed from waste orange peel (OP) in the removal of Cd(II) ions from aqueous solution via the batch process. The surface properties of the orange peel powder was studied using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (XRD) and Fourier transform infrared spectroscopy FT-IR). Operational conditions like temperature, contact time, sorbent dosage, solution pH and initial adsorbate concentration were investigated. The utmost uptake of Cd(II) ion was obtained at the contact time of 120 min, initial metal concentration of 240 mg/L, adsorbent dosage of 0.04 g/L, temperature of 45 °C and solution pH of 5.5 on the adsorption of Cd(II) ion. Equilibrium results showed that the orange peel adsorbent has an adsorption capacity of 27.916 mg/g as obtained from the Langmuir isotherm. The adsorption kinetics data followed a Pseudo-first-order kinetic model with correlation coefficient (R2) > 0.9 and low standard % error values. The adsorption process was found to be spontaneous, feasible and with enthalpy of 0.0046 kJ mol− 1 and entropy of -636.865 Jmol− 1K− 1 respectively. Results from the optimization study indicated that higher adsorbent dosage and lower Cd(II) ion concentration increased the percentage of Cd (II) ion removal. Thus, orange peel could be used in the removal of Cd(II) ion from aqueous solutions.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1086
Author(s):  
Asma Abdulkareem ◽  
Anton Popelka ◽  
Patrik Sobolčiak ◽  
Aisha Tanvir ◽  
Mabrouk Ouederni ◽  
...  

This paper addresses the preparation and characterization of efficient adsorbents for tertiary treatment (oil content below 100 ppm) of oil/water emulsions. Powdered low-density polyethylene (LDPE) was modified by radio-frequency plasma discharge and then used as a medium for the treatment of emulsified diesel oil/water mixtures in the concentration range from 75 ppm to 200 ppm. Plasma treatment significantly increased the wettability of the LDPE powder, which resulted in enhanced sorption capability of the oil component from emulsions in comparison to untreated powder. Emulsions formed from distilled water and commercial diesel oil (DO) with concentrations below 200 ppm were used as a model of oily polluted water. The emulsions were prepared using ultrasonication without surfactant. The droplet size was directly proportional to sonication time and ranged from 135 nm to 185 nm. A sonication time of 20 min was found to be sufficient to prepare stable emulsions with an average droplet size of approximately 150 nm. The sorption tests were realized in a batch system. The effect of contact time and initial oil concentrations were studied under standard atmospheric conditions at a stirring speed of 340 rpm with an adsorbent particle size of 500 microns. The efficiency of the plasma-treated LDPE powder in oil removal was found to be dependent on the initial oil concentration. It decreased from 96.7% to 79.5% as the initial oil concentration increased from 75 ppm to 200 ppm. The amount of adsorbed oil increased with increasing contact time. The fastest adsorption was observed during the first 30 min of treatment. The adsorption kinetics for emulsified oils onto sorbent followed a pseudo-second-order kinetic model.


2016 ◽  
Vol 14 (1) ◽  
pp. 175-187 ◽  
Author(s):  
Lăcrămioara (Negrilă) Nemeş ◽  
Laura Bulgariu

AbstractMustard waste biomass was tested as a biosorbent for the removal of Pb(II), Zn(II) and Cd(II) from aqueous solution. This strategy may be a sustainable option for the utilization of such wastes. The influence of the most important operating parameters of the biosorption process was analyzed in batch experiments, and optimal conditions were found to include initial solution pH 5.5, 5.0 g biosorbent/L, 2 hours of contact time and high temperature. Kinetics analyses show that the maximum of biosorption was quickly reached and could be described by a pseudo-second order kinetic model. The equilibrium data were well fitted by the Langmuir model, and the highest values of maximum biosorption capacity were obtained with Pb(II), followed by Zn(II) and Cd(II). The thermodynamic parameters of the biosorption process (ΔG, ΔH and ΔS) were also evaluated from isotherms. The results of this study suggest that mustard waste biomass can be used for the removal of heavy metals from aqueous media.


2015 ◽  
Vol 737 ◽  
pp. 537-540
Author(s):  
Yan Wei Guo ◽  
Hua Zhang ◽  
Zhi Liang Zhu

A novel Mg/Fe/Ce layered double hydroxide (LDHs) and its calcined product (CLDH) were synthesized and CLDH was used as adsorbents for the removal of chlorate ions. Results showed that the initial solution pH was an important factor influencing the chlorate adsorption. The adsorption behavior of chlorate followed the Langmuir adsorption isotherm with a maximum adsorption capacity of 18.2 mg/g. The adsorption kinetics of chlorate on CLDH can be described by the pseudo-second-order kinetic model. It was concluded that the CLDH material is a potential adsorbent for the purification of polluted water with chlorate.


Author(s):  
Amarnath P.C & Shashikala K. J. Praveen Kumar D. G., Kalleshappa C.M.,

In the present study we explored the adsorptive characteristics of 4-nitroaniline from synthetic aqueous solution onto bagasse fly ash (BFA). Batch experiments were carried out to determine the influence of parameters like initial pH (pH0), adsorbent dose (m), contact time (t) and initial concentration (C0) on the removal of 4-nitroaniline. The maximum removal of 4-nitroaniline was determined to be 98% at lower concentrations (50 mg/L) and 41% at higher concentrations (300 mg/L), using a BFA dosage of 10 g/L at 303K. Kinetic study of 4-nitroaniline removal by BFA was well represented by pseudo second-order kinetic model. The 4-nitroaniline desorption from 4-nitroaniline loaded BFA shows that only 27% and 36% of 4-nitroaniline could be recovered using ethyl alcohol and acetone respectively.


Sign in / Sign up

Export Citation Format

Share Document