scholarly journals Adsorptive Removal of Phosphate from Aqueous Solutions Using Low-Cost Volcanic Rocks: Kinetics and Equilibrium Approaches

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1312
Author(s):  
Dereje Tadesse Mekonnen ◽  
Esayas Alemayehu ◽  
Bernd Lennartz

The contamination of surface and groundwater with phosphate originating from industrial and household wastewater remains a serious environmental issue in low-income countries. Herein, phosphate removal from aqueous solutions was studied using low-cost volcanic rocks such as pumice (VPum) and scoria (VSco), obtained from the Ethiopian Great Rift Valley. Batch adsorption experiments were conducted using phosphate solutions with concentrations of 0.5 to 25 mg·L−1 to examine the adsorption kinetic as well as equilibrium conditions. The experimental adsorption data were tested by employing various equilibrium adsorption models, and the Freundlich and Dubinin-Radushkevich (D-R) isotherms best depicted the observations. The maximum phosphate adsorption capacities of VPum and VSco were calculated and found to be 294 mg·kg−1 and 169 mg·kg−1, respectively. A pseudo-second-order kinetic model best described the experimental data with a coefficient of correlation of R2 > 0.99 for both VPum and VSco; however, VPum showed a slightly better selectivity for phosphate removal than VSco. The presence of competitive anions markedly reduced the removal efficiency of phosphate from the aqueous solution. The adsorptive removal of phosphate was affected by competitive anions in the order: HCO3− >F− > SO4−2 > NO3− > Cl− for VPum and HCO3− > F− > Cl− > SO4−2 > NO3− for VSco. The results indicate that the readily available volcanic rocks have a good adsorptive capacity for phosphate and shall be considered in future studies as test materials for phosphate removal from water in technical-scale experiments.

2020 ◽  
Vol 5 (2) ◽  
pp. 58-64
Author(s):  
Arega Genetie Abetu ◽  
Adisu Befekadu Kebede

The contamination of surface and groundwater with phosphate originating from industrial, agricultural and household wastewater remains a serious environmental issue in low-income countries. Currently, demolished concrete is mainly recycled as aggregate for reconstruction and conventional wastewater treatment systems for removing phosphate are expensive and complex. In this study, we were aiming at testing crushed concrete as an efficient adsorbent for the removal of phosphate from aqueous solutions, obtained from the demolition of construction site. It can reduce pollution and landfill disposal by converting construction waste into valuable products and an alternative solution for phosphate removal. Batch adsorption experiments were conducted using phosphate solutions to examine the adsorption kinetic as well as equilibrium conditions. Results show that the phosphate adsorption of all absorbents follows the adsorption isotherms with a varying phosphate concentration from 3 mg/L to 18 mg/L, and the adsorption isotherms data are fitted well by Langmuir equation as compared with the Freundlich isotherm. The maximum phosphate adsorption (97.67 %) was obtained at a contact time of 120 min, an initial phosphate concentration of 10 mg/L, and a solution pH of 4. The pseudo second-order equation describes the experimental data has good agreement, with a correlation value of R2 = 0.99. The results obtained indicate that the environmentally available crushed concrete have a good adsorptive capacity for phosphate and shall be considered in future studies as test materials for phosphate removal from water in technical-scale experiment.


2021 ◽  
Vol 13 (16) ◽  
pp. 8994
Author(s):  
Eliana Contreras-López ◽  
Victor Miyashiro Kiyan ◽  
Jaime Porras Cerrón ◽  
Ana María Muñoz ◽  
Fernando Ramos-Escudero ◽  
...  

This study aimed to evaluate the adsorption capacity of an adsorbent obtained using sanky peel for the removal of phosphate from aqueous solutions. The study was conducted in two stages: (1) adsorbent preparation considering yield, phosphate removal, adsorption capacity, and textural characteristics; (2) an assessment of the effectiveness of using sanky peel as an adsorbent for removing phosphates from aqueous solutions. Batch adsorption was studied in aqueous solutions containing phosphate and calcium ions with the selected adsorbent. Adsorption kinetics and equilibrium isotherms were studied using mathematical models. The adsorption kinetics followed the pseudo-second-order, Elovich, and Weber–Morris models, thus demonstrating that adsorption rates were not controlled by multiple processes. Adsorption equilibrium data fitted best with the Dubinin–Radushkevich model. Finally, a Fourier transform infrared spectroscopy analysis revealed the presence of brushite spectra bands after adsorption. The results of this study can help better understand the use of sanky peel as an adsorbent and good alternative for aqueous phosphate adsorption.


2020 ◽  
Vol 13 ◽  
pp. 117862212096965
Author(s):  
Yohannis Fetene ◽  
Taffere Addis

Phosphorous from municipal and industrial wastewater is the main cause of eutrophication of rivers and lakes, because effluent quality from conventional secondary wastewater treatment plants does not meet the discharge standard that demands further treatment. Therefore, we investigated pumice as a potential low-cost adsorbent for the tertiary treatment of phosphate from municipal wastewater. The phosphate adsorption process reached equilibrium after 60 minutes contact time and achieved a removal efficiency of 94.4% ± 0.7% for an adsorbent dose of 10 g/L in 3 mg/L phosphate solution. The highest phosphate removal was recorded at pH 7. The experimental data best fitted with the Redlich-Peterson isotherm and the pseudo-second-order kinetic models. The coexisting anions decreased phosphate adsorption in the order of mixture >SO42– > HCO3− > NO3− > Cl− > CO3−. Pumice removed 95% ± 0.2% of phosphate from effluents of the secondary treatment unit of a municipal wastewater treatment plant. Furthermore, effective regeneration of saturated pumice was possible with a 0.2 M NaOH solution. Therefore, pumice could be a technically workable low-cost reusable adsorbent for phosphate removal from wastewater as a tertiary treatment to curb eutrophication of surface waters. However, further column adsorption study is recommended for a continuous flow system to optimize process design variables and scale up for field applications.


2014 ◽  
Vol 49 (4) ◽  
pp. 307-318 ◽  
Author(s):  
C. Liu ◽  
Y. Yang ◽  
N. Wan

Adsorption of phosphate onto construction solid waste (CSW) was investigated in a batch system. CSW as an inescapable by-product of the construction and demolition process, was used as a composite adsorbent for the removal of phosphate in this study. The adsorption kinetics was investigated under various parameters such as contact time, pH, CSW dosage, initial phosphate concentration and particle size. Greater percentage of phosphate was removed with decrease in the initial concentration and increase in the amount of CSW used. Adsorption of phosphate was pH dependent, and maximum phosphate immobilisation capacity was obtained in alkaline condition. Lagergren first-order, second-order, intra-particle diffusion and external diffusion model were used to test the experimental data. Kinetic analysis showed that the adsorption was best fitted with the pseudo-second-order kinetic model. Adsorption mechanism studies revealed that both external mass transfer and intra-particle diffusion had rate limiting effects on the removal process. These results demonstrated that the CSW could be used as a low-cost adsorbent media for phosphate removal, and the data were relevant for optimal design of wastewater treatment plants.


2018 ◽  
Vol 250 ◽  
pp. 06013 ◽  
Author(s):  
Nur Atikah Abdul Salim ◽  
Noorul Hudai Abdullah ◽  
Muhammad Rijaluddin Khairuddin ◽  
Mohd A’ben Zulkarnain Rudie Arman ◽  
Mohd Hairul Khamidun ◽  
...  

Excessive amount of phosphate released from wastewater can cause eutrophication to the receiving waters. Adsorption technique has been used to remove phosphate from aqueous solutions. The use of waste mussel shell (WMS) to remove phosphate from aqueous solutions and application of several kinetic and isotherm models to describe the adsorption of phosphate onto WMS were conducted in batch experiments. The phosphate adsorption by the WMS was examined with respect to solute concentration, contact time and adsorbent dose. The phosphate removal efficiencies obtained were 46.7, 57.6, 64.1, 70.8 and 75.2% at 144 h contact time for WMS dosage of 2, 4, 6, 8 and 10 g, respectively. Physical and chemical properties of WMS including surface physical morphology and elemental compositions were characterized. A comparison of kinetic models applied to the phosphate adsorption onto WMS was evaluated for the pseudo-first order and pseudo-second order model. The experimental data fitted very well with the pseudo-second order kinetic model (R2 > 0.984), which indicated the adsorption process was chemisorption. In the isotherm studies, the Langmuir and Freundlich isotherm models were applied. The results indicated that the use of Freundlich equation is well described with the phosphate adsorptions onto WMS (R2 = 0.968), suggesting the heterogeneity of the adsorbent surface. The experimental results suggested the use of WMS as an excellent adsorption material for phosphate removal from aqueous solutions, giving new insights into environmental engineering practices.


2017 ◽  
Vol 77 (5) ◽  
pp. 1213-1221
Author(s):  
Sara Abdi ◽  
Masoud Nasiri

Abstract The purpose of this study was to investigate the removal of Fast Green FCF dye from aqueous solutions using Flower Gel in a batch adsorption process. The effect of different parameters such as pH, contact time, adsorbent dosage, stirrer speed and temperature were studied, and various isotherms including Langmuir, Freundlich and Tempkin were applied. The adsorbent characteristics were determined by microscopic analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction and ultraviolet-visible (UV-vis) spectrophotometry. The results showed that the equilibrium experimental data fitted well to the Langmuir isotherm and the maximum adsorption capacity for this adsorbent was 58.82 mg/g. The adsorption kinetic data followed the pseudo-second-order kinetic model and the thermodynamic parameters of the adsorption, such as Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°), showed that the Fast Green FCF adsorption process by Flower Gel was spontaneous and exothermic in nature.


2016 ◽  
pp. 39-48
Author(s):  
Pathompong Vibhatabandhu ◽  
Sarawut Srithongouthai

Biosorptionis an effective process for removal and recovery of heavy metal ions from aqueous solutions. In the present study, batch adsorption experiments were carried out for the removal of copper (Cu II) from aqueous solutions using cuttlebone powder (<100 μm)as a bio-adsorbent. The effects of initial pH, adsorbent dosage, initial concentration, and contact time on adsorption efficiency and capacity were studied to evaluate the optimum conditions for copper removal.The results found optimal conditions at initial pH of 5.0, 10 g L-1cuttlebone, 500 mg L-1initial concentration of Cu II in solution, and 150 min of equilibrium time.The Langmuir isotherm and pseudo-second order kinetic model were fitted to the experimental adsorption data. The maxi-mum adsorption capacity calculated from theLangmuir isotherm was 54.05 mg g-1. This result shows that cuttlebone is an effective bio-adsorbent, constituting a promising, efficient, low-cost, and eco-friendly technology bio-sorbent for reducing copper pollution during wastewater treatment.


2002 ◽  
Vol 2 (5-6) ◽  
pp. 217-224 ◽  
Author(s):  
Z. Reddad ◽  
C. Gérente ◽  
Y. Andrès ◽  
P. Le Cloirec

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ &gt; Cd2+ &gt; Zn2+ &gt; Cu2+ &gt; Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ &gt; Cu2+ &gt; Zn2+ &gt; Cd2+ &gt; Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.


2020 ◽  
Vol 10 (5) ◽  
pp. 1738
Author(s):  
Kay Thwe Aung ◽  
Seung-Hee Hong ◽  
Seong-Jik Park ◽  
Chang-Gu Lee

Polyacrylonitrile (PAN) fibers were prepared via electrospinning and were modified with diethylenetriamine (DETA) to fabricate surface-modified PAN fibers. The surface-modified PAN fibers were used to evaluate their adsorption capacity for the removal of Cu(II) from aqueous solutions. Batch adsorption experiments were performed to examine the effects of the modification process, initial concentration, initial pH, and adsorbent dose on the adsorption of Cu(II). Kinetic analysis revealed that the experimental data fitted the pseudo-second-order kinetic model better than the pseudo-first-order model. Adsorption equilibrium studies were conducted using the Freundlich and Langmuir isotherm models, and the findings indicated that the PAN fibers modified with 85% DETA presented the highest adsorption capacity for Cu(II) of all analyzed samples. Moreover, the results revealed that the Freundlich model was more appropriate than the Langmuir one for describing the adsorption of Cu(II) onto the modified fibers at various initial Cu(II) concentrations. The maximum adsorption capacity was determined to be 87.77 mg/g at pH 4, and the percent removal of Cu(II) increased as the amount of adsorbent increased. Furthermore, the surface-modified PAN fibers could be easily regenerated using NaOH solution. Therefore, surface-modified PAN fibers could be used as adsorbents for the removal of Cu(II) from aqueous solutions.


2020 ◽  
Vol 38 (7-8) ◽  
pp. 254-270
Author(s):  
Yuanrong Zhu ◽  
Xianming Yue ◽  
Fazhi Xie

Reducing input of phosphorus is the key step for control of eutrophication and algal blooming in freshwater lakes. Adsorption technology is a cost-effective technology for phosphate removal in water for the purpose. Thus, in this study, a novel Fe–Mn–La tri-metal composite sorbent was developed, and then evaluated for phosphate removal. The results showed that the maximum adsorption capacity could be approached to 61.80 mg g−1 at 25°C under pH of 6.03. Adsorption of phosphate by Fe–Mn–La tri-metal composite adsorbent fitted better by pseudo-second-order kinetic equation and Langmuir model, which suggested that the adsorption process was surface chemical reactions and mainly in a monolayer coverage manner. The thermodynamic study indicated that the adsorption reaction was an endothermic process. The phosphate removal gradually decreased with the increasing of pH from 3.02 to 11.00. The sequence of coexisting anions competing with phosphates was that CO32− > Cl− > SO42− > NO3−. Dissolved organic matter, fulvic acid as a representative, would also decrease adsorption capacities of phosphate by Fe–Mn–La tri-metal composite adsorbents. Adsorption capacity would be decreased with increasing addition of adsorbents, while removal efficiency would be increased in this process. The Fe–Mn–La tri-metal composite adsorbent showed a good reusability when applied to removal of dissolved phosphate from aqueous solutions. The Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy analyses indicated that some hydroxyl groups (–OH) on the surface of adsorbent were replaced by the adsorbed PO43−, HPO42−, or H2PO4−. Aggregative results showed that the novel Fe–Mn–La tri-mental composite sorbent is a very promising adsorbent for the removal of phosphate from aqueous solutions.


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