scholarly journals Polystyrene Magnetic Nanocomposites as Antibiotic Adsorbents

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1313 ◽  
Author(s):  
Leili Mohammadi ◽  
Abbas Rahdar ◽  
Razieh Khaksefidi ◽  
Aliyeh Ghamkhari ◽  
Georgios Fytianos ◽  
...  

There are different ways for antibiotics to enter the aquatic environment, with wastewater treatment plants (WWTP) considered to be one of the main points of entrance. Even treated wastewater effluent can contain antibiotics, since WWTP cannot eliminate the presence of antibiotics. Therefore, adsorption can be a sustainable option, compared to other tertiary treatments. In this direction, a versatile synthesis of poly(styrene-block-acrylic acid) diblock copolymer/Fe3O4 magnetic nanocomposite (abbreviated as P(St-b-AAc)/Fe3O4)) was achieved for environmental applications, and particularly for the removal of antibiotic compounds. For this reason, the synthesis of the P(St-b-AAc) diblock copolymer was conducted with a reversible addition fragmentation transfer (RAFT) method. Monodisperse superparamagnetic nanocomposite with carboxylic acid groups of acrylic acid was adsorbed on the surface of Fe3O4 nanoparticles. The nanocomposites were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) analysis. Then, the nanoparticles were applied to remove ciprofloxacin (antibiotic drug compound) from aqueous solutions. The effects of various parameters, such as initial drug concentration, solution pH, adsorbent dosage, and contact time on the process were extensively studied. Operational parameters and their efficacy in the removal of Ciprofloxacin were studied. Kinetic and adsorption isothermal studies were also carried out. The maximum removal efficiency of ciprofloxacin (97.5%) was found at an initial concentration of 5 mg/L, pH 7, adsorbent’s dosage 2 mg/L, contact time equal to 37.5 min. The initial concentration of antibiotic and the dose of the adsorbent presented the highest impact on efficiency. The adsorption of ciprofloxacin was better fitted to Langmuir isotherm (R2 = 0.9995), while the kinetics were better fitted to second-order kinetic equation (R2 = 0.9973).

2019 ◽  
Vol 6 (2) ◽  
pp. 81-88 ◽  
Author(s):  
Dariush Naghipour ◽  
Abdoliman Amouei ◽  
Kamran Taher Ghasemi ◽  
Kamran Taghavi

Background: Metoprolol (MTP) with its low biodegradability is one of the most dominant micropollutant in the effluent of wastewater treatment plants. The aim of this study was to investigate the removal of metoprolol from aqueous solutions by the activated carbon prepared from pine cones. Methods: The pine cones were activated using thermal activation method. Characteristics of the adsorbent were determined using Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). In this study, the influent of different parameters such as pH, contact time, initial concentrations of metoprolol, adsorbent dose, temperature, adsorption isotherms, and kinetics were investigated. Results: The maximum removal efficiency of MTP (89.2%) was obtained at pH=8.5, adsorbent dose=1.5 g, contact time=60 min, and initial concentration=50 mg/L. By increasing the adsorbent dose, the removal efficiency also increased, but the adsorption capacity decreased, however, by increasing the initial concentration, the removal efficiency decreased, but the adsorption capacity increased. The isotherm experimental data for metoprolol was best fitted using the Langmuir model, and kinetic data were better described by pseudo-second-order kinetic model. The thermodynamic study indicated that the adsorption of MTP by the adsorbent was feasible, spontaneous, and endothermic. Conclusion: MTP removal by the activated carbon prepared from pine cones showed that this natural adsorbent is appropriate for removal of metoprolol from aqueous solutions regarding cost, efficiency, and production method.


2018 ◽  
Vol 382 ◽  
pp. 307-311 ◽  
Author(s):  
Jumaeri ◽  
Sri Juari Santosa ◽  
Sutarno

Adsorption of anionic dyes Congo Red (CR) on HDTMA surfactant-modified zeolite A has been studied. The zeolite A, which is synthesized from coal fly ash, was modified with surfactant hexdeciltrimethylammonium bromide (HDTMA-Br) as much as 200% cation exchange capacity (CEC) of the zeolite. The effect of pH, contact time and initial concentration on the CR adsorption has been evaluated.The adsorption was carried out in a batch reactor at various pH, contact time and initial concentration on the given temperature. The amount CR adsorption varies as a function of pH, contact time and initial concentration of solution. Adsorption model of Langmuir and Freundlich from empirical data is used for this experiment. The Langmuir isotherm is more suitable for this adsorption. The experimental data fulfilled pseudo second-order kinetic models. The surfactant-modified zeolite A is more effective than zeolite A without modified on the adsorption of CR in aqueous solution.


2021 ◽  
Author(s):  
Mehdi Ahmadi ◽  
rozhan feizi

Abstract Azo dyes due to the presence of benzene ring, toxicity, mutagenicity, carcinogenicity and low biodegradability have become a major problem in the aqueous environment. In this study, Zero Valent Iron (ZVI) was employed as a catalyst to activate persulfate (PS) and hydrogen peroxide (H2O2) for removal of Sunset Yellow (SY) from aqueous solutions using integrated H2O2/ZVI/PS process. The effects of operational parameters (solution pH, H2O2 concentration, PS concentration, and ZVI dose) were studied on SY removal. According to the results, about 100% efficiency was obtained by the H2O2/ZVI/PS for dye removal at: pH = 3, ZVI 50 mg/L, 1 mM H2O2 concentration, 1 mM PS concentration, and 30 min reaction time. The kinetic study implied that the H2O2/ZVI/PS process followed the first-order kinetic model. The total organic carbon (TOC) test showed that about 65% of mineralization was achieved after 30 min. Moreover, the ZVI particles showed a suitable efficiency after five cycles, and hence, it can be used as an eco-friendly, cost effective and reusable catalyst for the treatment of wastewaters contaminated with such dyes.


2020 ◽  
Author(s):  
Eman Alabbad

Abstract Background Water contamination has increasingly become a significant problem affecting the welfare of living organisms perceived to be aquatic beneficiaries. The nature and origin of the contaminant always determines the purification techniques. The most common contaminants in wastewater include organic compounds such as dyes that must be eliminated to enhance water purity and safety.Result The results indicate that the removal of DY50 by the modified chitosan was affected by the solution pH, sorbent dosage, initial DY50 concentration, contact time, and temperature. The experimental data were fitted to the Langmuir, Freundlich, and Temkin isotherms, and Langmuir isotherm showed the best fit. The kinetic data were fitted to the pseudo-first-order and pseudo-second-order rate equations. The removal rate was 97.9% by chemisorption components after the three hours at about 0.05 g of sorbent dose and 100 ppm of the Direct Yellow 50 dye initial concentration. The adsorption behavior of the modified chitosan for the removal of DY50 was well-described using the pseudo-second-order kinetic model, Intraparticle diffusion analysis was also conducted. The thermodynamic properties such as free energy (∆G), enthalpy (∆H), and entropy (∆S), in addition to the intra-particle diffusion rate were similarly defined.Conclusion The pH, initial DY50 concentration, sorbent dosage, adsorption temperature, and contact time had a significant effect on the adsorption of DY50 by chitosan-iso-vanillin.


Author(s):  
Ketyla K. R. do Nascimento ◽  
Fernando F. Vieira ◽  
Marcello M. de Almeida ◽  
Josué da S. Buriti ◽  
Aldre J. M. Barros ◽  
...  

ABSTRACT The disposal of industrial wastewater into aquatic bodies without proper treatment can cause severe damage to the environment and human health. The objective of this study was to perform the drying of the sweet orange (Citrus sinensis L. Osbeck) peel cultivar Pêra and evaluate the viability of its use as biosorbent in the removal of a direct dye. Drying was carried out in an oven with air circulation at temperatures of 60 and 80 ºC. The mathematical models of Page, Henderson and Pabis, Logarithmic, Midilli and Two-term exponential were fitted to the moisture data as a function of time. The material was characterized by scanning electron microscopy, point of zero charge, and infrared spectroscopy. In the adsorption study, a complete 24 factorial design was used to analyze the influence of mass, initial concentration, solution pH and contact time on adsorbed quantity (qt) and removal percentage of the dye (R%). In the drying, the two-term exponential model fitted best to the experimental data. The characterization of the material indicated that the adsorbent has zero charge point of 3.5 and porous structure, and the infrared analysis indicated the presence of carboxylic and hydroxyl groups. In the adsorption, the adsorbed quantity of the dye increased under conditions of lower pH and biosorbent mass and higher initial concentration and contact time. The removal percentage of dye increases with higher biosorbent mass. The biosorbent used is a promising waste for the adsorption of the burgundy-16 dye.


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+.


Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1381
Author(s):  
Dereje Tadesse Mekonnen ◽  
Esayas Alemayehu ◽  
Bernd Lennartz

High loadings of wastewater with phosphors (P) require purification measures, which can be challenging to realize in regions where the technical and financial frame does not allow sophisticated applications. Simple percolation devices employing various kinds of adsorbents might be an alternative. Here, we investigated the application of leftover coal, which was collected from Ethiopian coal mining areas, as an adsorbent for the removal of phosphate from aqueous solutions in a classical slurry batch set-up. The combined effects of operational parameters such as contact time, initial concentration, and solution pH on P retention efficiency was studied employing the Response Surface Methodology (RSM). The maximum phosphate adsorption (79% removal and 198 mg kg−1 leftover coal) was obtained at a contact time of 200 min, an initial phosphate concentration of 5 mg/L, and a solution pH of 2.3. The Freundlich isotherm was fitted to the experimental data. The pseudo second-order equation describes the experimental data well, with a correlation value of R2 = 0.99. The effect of temperature on the adsorption reveals that the process is exothermic. The results demonstrate that leftover coal material could potentially be applied for the removal of phosphate from aqueous media, but additional testing in a flow-through set-up using real wastewater is required to draw definite conclusions.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Saeedeh Hashemian ◽  
Khaterah Salari ◽  
Hamila Salehifar ◽  
Zahra Atashi Yazdi

Activated carbon developed from agricultural waste orange peel (COP) was prepared. COP was characterized using Fourier infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and BET. COP has surface area and mean pore diameter of 225.6 m2 g−1and 22.40 nm, respectively. The removal of violet B (VB) and violet 5R (V5R) from aqueous solutions by COP was investigated. The effect of operational parameters such as contact time, pH, initial dye concentration, and adsorbent dosage on the adsorption of dyes was investigated. Maximum dye was removed within 30 min of contact time at pH > 7. Two common models, the Langmuir and Freundlich isotherms, were used to investigate the interaction of dye and COPs. The isotherm evaluations revealed that the Langmuir model provides better fit to the experimental data than the Freundlich model. The adsorption of VB and V5R onto COP was followed by pseudo-second-order kinetic model with a good correlation (R2>0.99). Activation energies 5.47 and 29.7 KJ mol−1were determined for violet B and violet 5R, respectively. The rate of adsorption of violet 5R was faster than that of violet B (kV5R>kVB). The prepared COP could thus be used as promising adsorbent for removal of organic dyes, especially azo dye, from polluted water. The solid COP could be conveniently regenerated after adsorption.


2014 ◽  
Vol 661 ◽  
pp. 51-57
Author(s):  
Mohd Zawawi Mohamad Zulhelmi ◽  
Alrozi Rasyidah ◽  
Senusi Faraziehan ◽  
Mohamad Anuar Kamaruddin

Biosorption process is considered as economical treatment to remove metal from the aqueous solution compared to other established methods. In this study, Saccharomyces cerevisiae was used as biosorbent and subject to immobilization process which consists of ethanol treatment for the removal of binary metals, lead (II) and nickel (II) from aqueous solution. Response surface methodology (RSM) was used to optimize effective parameters condition and the interaction of two or more parameters in order to obtain high removal of the binary metals. The parameters that have been studied were initial concentration of binary metals solution (10 - 60 mg/L), biosorbent dosage (0.2 - 1.0 g), pH (pH 2 - pH 6) and contact time (30 - 360 minutes) towards lead (II) and nickel (II) ions removal. Based on analysis of variance (ANOVA), biosorbent dosage, solution pH and contact time factor were found significant for both responses. Through optimization procedure, the optimum condition for lead (II) and nickel (II) ions removal were obtained at initial concentration of 10.0 mg/L, biosorbent dosage of 1.0 g, solution pH of pH 6, and contact time of 360.00 minutes, which resulted in 95.08 % and 21.09 % removal of lead (II) and nickel (II) ions respectively.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ilesanmi Osasona ◽  
Olubode O. Ajayi ◽  
Albert O. Adebayo

The capability of cow hoof (CH) to remove Zn(II) from aqueous solution under the influence of sorbent size, solution pH, contact time, and sorbent dosage was investigated through batch studies. Equilibrium studies were conducted at three different temperatures (298, 308, and 318 K) by contacting different concentrations of Zn(II) solution with a known weight of cow hoof. The biosorption of Zn onto cow hoof was found to increase with increase in the mass of sorbent used while the biosorption efficiency was found to decrease with increase in sorbent particle size. The optimum conditions of pH 4 and contact time of 60 minutes were required for maximum removal of Zn(II) by cow hoof (mesh size 212 µm). The equilibrium data were modelled using Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models. The data were best fitted by Langmuir model. The kinetic data were analysed using Lagergren kinetic equations and these were well fitted by the pseudo-second-order kinetic model. The thermodynamic parameters showed that the biosorption process was feasible, spontaneous, and endothermic.


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