scholarly journals Remarkable phosphate removal from saline solution by using a novel trimetallic oxide nanocomposite

Author(s):  
Mahsa Alimohammadi ◽  
Bita Ayati

Abstract Phosphate removal is an important measure to control eutrophication in aquatic environments, as it inhibits algal bloom. Salinity exists in these media along with high phosphate and currently available phosphate removal methods function poorly under this condition. In this study, the main objective is to fabricate a nanocomposite to improve and accelerate phosphate removal from saline solutions. To achieve this goal, Fe3O4/ZnO and a novel nanoadsorbent, Fe3O4/ZnO/CuO, were synthesized. Their characteristics were determined using FE-SEM, EDX, FT-IR, and XRD analyses, and their capability to adsorb phosphate from saline solutions was investigated and compared. The overall results suggest that the trimetallic oxide nanocomposite has a great potential for the efficient removal of phosphate, in comparison with Fe3O4/ZnO. Experiments showed that Fe3O4/ZnO/CuO exhibited a remarkable sorption capacity of 156.35 mg P/g, fast sorption kinetic, strong selectivity for phosphate even in the presence of a high concentration of salinity (60 mg/L), and a wide applicable pH range of 3–6. Furthermore, using Fe3O4/ZnO/CuO, even a low dosage of 0.1 g/L was sufficiently enough to reach an adsorption efficiency of 96.13% within 15 min compared to Fe3O4/ZnO (80.47% within 30 min). Moreover, the pseudo-second-order kinetic model best described the experimental adsorption data for both nanocomposites.

2020 ◽  
Vol 82 (8) ◽  
pp. 1535-1546
Author(s):  
Dajun Ren ◽  
Hongyan Yu ◽  
Jian Wu ◽  
Zhaobo Wang ◽  
Shuqin Zhang ◽  
...  

Abstract In this study, rice straw was used to prepare biomass carbon, which was modified with KOH and cetyltrimethylammonium bromide (CTAB) to obtain modified biomass carbon (MBC). The biomass carbon (BC) before and after modification was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR), and the surface morphology, crystal structure and surface group characteristic BC were explored. The specific surface area and micropores of the modified biomass carbon increased significantly, the crystallinity was higher, and the pore structure was more clearly found. The adsorption performance of MBC for 2,4-dichlorophenol (2,4-DCP) was investigated. The results showed that under the best adsorption conditions ((2,4-DCP concentration (200 mg/L), MBC dosage (50 mg), pH (5.5), and loading time (60 min), temperature (room temperature)), the removal rate of 2,4-DCP was up to 42.5%, and adsorption capacity was 85.13 mg/g. The adsorption of 2,4-DCP on MBC materials was better explained by the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. It was believed that the adsorption of 2,4-DCP by MBC was the monolayer adsorption process on the uniform surface of MBC at high concentration, and there was no interaction between the 2,4-DCP and MBC adsorbate during this process.


2014 ◽  
Vol 675-677 ◽  
pp. 647-653
Author(s):  
Hong Bin Lv ◽  
Yao Li ◽  
Wan You Zhang ◽  
Li Juan Xi

Mg-Fe hydrotalcite-like compounds (Mg-Fe-HTLCs) were synthesized via hydrothermal method, and characterized by XRD and FT-IR. The roasted products were used to remove sulfate ions by the adsorptive ability from aqueous solution. The effects of adsorbent dosage, initial pH and temperature on the sulfate ions removal were fully investigated, and the adsorption kinetics and adsorption isotherms were also studied. Results showed that the synthesized materials with CO32- as the interlayer anions had fine crystallinity. The materials of Mg-Fe hydrotalcite-like compounds had a very good adsorption capacity for aqueous solution with the initial sulfate ions concentration was 500mg/L, pH range from 4 to 8 and temperature of 35°C. Moreover, the adsorption equilibrium was about 90 min under the optical condition. The experimental data showed a good compliance with the pseudo-second-order kinetic model, and the adsorption isotherm data met Langmuir models well. It was found that the maximal adsorption capacity reached 151.51mg/g.


2018 ◽  
Vol 21 (8) ◽  
pp. 583-593 ◽  
Author(s):  
Sara Rahnama ◽  
Shahab Shariati ◽  
Faten Divsar

Objective: In this research, a novel magnetite titanium dioxide nanocomposite functionalized by amine groups (Fe3O4@SiO2@TiO2-NH2) was synthesized and its ability for efficient removal of Acid Fuchsine as an anionic dye from aqueous solutions was investigated. Method: The core-shell structure of Fe3O4@SiO2@TiO2 was prepared using Fe3O4 as magnetic core, tetra ethyl orthosilicate as silica and tetra butyl titanate as titanium source for shell. The synthesized nanocomposites (particle size lower than 44 nm) were characterized by FT-IR, XRD, DRS, SEM and TGA instruments. The various experimental parameters affecting dye removal efficiency were investigated and optimized using Taguchi fractional factorial design. Results: The synthesized adsorbent showed the highest removal efficiency of Acid Fuchsine (99 %) at pH= 3.5, without salt addition and during stirring at contact times less than 10 minutes. The study of kinetic models at two concentration levels showed the fast dye sorption on the surface of proposed nanocomposites with pseudo second order kinetic model (R2=1). Also, the fitting of Acid Fuchsine sorption data to Freundlich, Langmuir and Temkin isotherms suggested that Freundlich model gave a better fitting than other models (R2=0.9936, n=2). Conclusion: Good chemical stability, excellent magnetic properties, very fast adsorption kinetics and high removal efficiency make the synthesized nanocomposite as a proper recoverable sorbent for removal of Acid Fuchsine dye from wastewaters.


2017 ◽  
Vol 75 (6) ◽  
pp. 1500-1511 ◽  
Author(s):  
Shengjiong Yang ◽  
Pengkang Jin ◽  
Xiaochang C. Wang ◽  
Qionghua Zhang ◽  
Xiaotian Chen

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.


Author(s):  
Mohamed Nasser Sahmoune ◽  
Krim Louhab ◽  
Aissa Boukhiar

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.


2012 ◽  
Vol 11 (02) ◽  
pp. 1250019 ◽  
Author(s):  
RAJESH KUMAR ◽  
S. K. JAIN

This study was carried out to evaluate the environmental application of functionalized carbon nanotubes through the experimental removal of strontium (II) from water. The aim was to find the optimal condition for the removal of strontium from water under different conditions such as initial concentration of strontium, contact time and neutral pH. The functionalized multi wall carbon nanotubes (f-MWCNT) were characterized by FT-IR and scanning electron microscopy (SEM). The adsorption isotherms were correlated to Freundlich and Langmuir models and it was found that the adsorption data could be fitted better by Langmuir model than Freundlich one. The kinetic data shows that the adsorption describes well with the pseudo-second order kinetic model. Functionalized MWCNT can be used as good adsorbent for the removal of the strontium ions from polluted water according to results.


2011 ◽  
Vol 413 ◽  
pp. 148-153 ◽  
Author(s):  
Xue Na Hu ◽  
Ya Han ◽  
Jia Yan Li ◽  
Jun Yan Wu ◽  
Jian Rong Chen ◽  
...  

Thiol-functionalized MCM-48 (SH-MCM-48) was synthesized by co-condensation method, with co-templates of cetyltrimethylammonium bromide (CTAB) and nonionic poly (ethylene oxide)–poly (propylene oxide)–poly (ethylene oxide) triblock copolymer (Pluronic P123). The resulting material was characterized by XRD and FT-IR spectrum. The potential of SH-MCM-48 for adsorption Zn (II) from aqueous solution was examined. Batch adsorption studies were carried out to investigate the effect of experimental parameters including pH, metal ions concentration and adsorption time. The maximum adsorption capacities of Zn (II) onto SH-MCM-48 were 30.12, 34.01 and 38.02 mg g-1 at the temperature of 303, 313 and 323K, respectively. The adsorption kinetics data were found to follow the pseudo-second-order kinetic model, and adsorption isotherms were fitted well with Langmuir and Freundlich models. Moreover, the adsorption thermodynamic parameters (△G0, △H0 and △S0) were measured, and indicated that the adsorption was an exothermic and spontaneous process.


Author(s):  
Xin Lu ◽  
Beibei Tang ◽  
Qi Zhang ◽  
Lizhu Liu ◽  
Ruqin Fan ◽  
...  

Batch experiments were conducted to investigate the adsorption characteristics of tetracycline (TC), and the interactive effects of copper (Cu) on the adsorption of TC onto water hyacinth roots. TC removal efficiency by water hyacinth roots was ranging from 58.9% to 84.6%, for virgin TC, 1:1 TC-Cu and 1:2 TC-Cu. The Freundlich isotherm model and the pseudo-second-order kinetic model fitted the adsorption data well. Thermodynamics parameters ΔG0 for TC were more negative in the TC plus Cu than the TC-only treatments, indicating the spontaneity of TC adsorption increased with increasing of Cu concentrations. An elevated temperature was associated with increasing adsorption of TC by water hyacinth roots. The additions of Cu(II) significantly increased TC adsorption onto water hyacinth roots within the pH range 4 to 6, because copper formed a strong metal bridge between root surface and TC molecule, facilitating the adsorption of TC by roots. However, Cu(II) hindered TC adsorption onto water hyacinth roots on the whole at pH range from 6–10, since the stronger electrostatic repulsion and formation of CuOH+ and Cu(OH)2. Therefore, the interaction between Cu(II) and TC under different environmental conditions should be taken into account to understand the environmental behavior, fate, and ecotoxicity of TC.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaodong Li

Using straw and urea as raw materials, biochar (BC) and g-C3N4 were prepared by oxygen-free pyrolysis at 300°C and 550°C. BC/g-C3N4 was prepared by loading different amounts of g-C3N4 onto the surface of biochar and characterized by SEM and FT-IR. The adsorption effect on methylene blue (MB) was investigated from the aspects of dosage and pH. The studies of adsorption equilibrium isotherms and the kinetic and the thermodynamic parameters on the BC/g-C3N4 adsorbents are discussed. The results showed that BC/g-C3N4 0.16 g/L with a doping ratio of 1 : 3 was added to the MB solution with an initial concentration of 50 mg/L and pH=11. The adsorption rate and adsorption amount were 96.72% and 302.25 mg/g, respectively. The adsorption process included surface adsorption and intraparticle diffusion, which conformed to the pseudo-second-order kinetic model and Langmuir-Freundlich model. Thermodynamic parameters (ΔG0<0, ΔH0>0, and ΔS0>0) showed that the adsorption reaction is spontaneous, which positively correlated with temperature.


2015 ◽  
Vol 71 (11) ◽  
pp. 1611-1619 ◽  
Author(s):  
Jun Liu ◽  
Hongyan Du ◽  
Shaowei Yuan ◽  
Wanxia He ◽  
Pengju Yan ◽  
...  

Alkaline deoxygenated graphene oxide (aGO) was prepared through alkaline hydrothermal treatment and used as adsorbent to remove Cd(II) ions from aqueous solutions for the first time. The characterization results of transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and Fourier transform infrared (FT-IR) spectra indicate that aGO was successfully synthesized. The batch adsorption experiments showed that the adsorption kinetics could be described by the pseudo-second-order kinetic model, and the isotherms equilibrium data were well fitted with the Langmuir model. The maximum adsorption capacity of Cd(II) on aGO was 156 mg/g at pH 5 and T = 293 K. The adsorption thermodynamic parameters indicated that the adsorption process was a spontaneous and endothermic reaction. The mainly adsorption mechanism speculated from FT-IR results may be attributed to the electrostatic attraction between Cd2+ and negatively charged groups (–CO−) of aGO and cation-π interaction between Cd2+ and the graphene planes. The findings of this study demonstrate the potential utility of the nanomaterial aGO as an effective adsorbent for Cd(II) removal from aqueous solutions.


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