Phosphorus removal from aqueous solutions by sorption on two volcanic soils

2003 ◽  
Vol 83 (5) ◽  
pp. 547-556 ◽  
Author(s):  
L. Zeng ◽  
R. L. Johnson ◽  
X. Li ◽  
J. Liu

The use of low-cost materials for P removal is of interest for developing cost-effective techniques for preventing P pollution. This paper reports a study on phosphate removal from aqueous solutions by sorption on two volcanic soils. The raw and HCl-treated soils were characterized with respect to oxalate-extractable and dithionite-extractable Al and Fe contents, surface area, and P sorption capacities. The phosphate sorption isotherms, kinetics, pH effects, and desorbability were evaluated in batch tests. The measured isotherm data were well fitted by the Freundlich and Temkin models. Phosphate sorption on these soils was relatively fast and the kinetics could be satisfactorily described by the simple Elovich and power function equations. The two soils had maximum phosphate sorption capacities of approximately 0.85 and 1.35 mg g-1 gram of soil at pH 6.0–6.5. The pH had different effects on phosphate sorption on these soils, likely due to either calcium phosphate precipitation or surface repulsion of the negatively charged phosphate species at a higher pH. Column flow-through tests using both synthetic phosphate solution and liquid swine manure confirmed the phosphate removal ability of the volcanic soils. It was concluded that volcanic soils could be potential low-cost materials for controlling P pollution from agricultural sources. Key words: Phosphate removal, volcanic soil, sorption, isotherm, kinetics, desorption

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 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.


2013 ◽  
Vol 67 (5) ◽  
pp. 983-988 ◽  
Author(s):  
Shuncai Wang ◽  
Rongzhuo Yuan ◽  
Xueyong Yu ◽  
Chaojie Mao

This study explored the feasibility of utilizing lead–zinc tailings for phosphate removal in laboratory experiments. The adsorption isotherm, kinetics and pH effect were examined in batch experiments. The Freundlich and Langmuir isotherm models were used for data fitting. The adsorption kinetics can be best described by the simple Elovich equation. The phosphate adsorption tends to decrease with the increase of pH, from 0.37 mg P/g at pH 2.05 to 0.12 mg P/g at pH 7.01, and tends to increase from 0.12 mg P/g at pH 7.01 to 0.64 mg P/g at pH 12.52. The actual phosphate removal on the tailings could be a consequence of adsorption and precipitation reactions with Fe, Al and Ca. Due to their low cost, this type of tailings has the potential to be utilized for cost-effective removal of phosphate from wastewater.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5820 ◽  
Author(s):  
Sara Gonzalez-Rodriguez ◽  
Maria Luisa Fernandez-Marcos

Volcanic soils cover 1% of the Earth’s surface but support 10% of the world’s population. They are among the most fertile soils in the world, due to their excellent physical properties and richness in available nutrients. The major limiting factor for plant growth in volcanic soils is phosphate fixation, which is mainly attributable to active species of aluminium and iron. The sorption and desorption of phosphate is studied on the surface horizons of two African agricultural soils, a silandic Andosol (Rwanda) and a vitric Andosol (São Tomé and Principe). Both soils are slightly acid. The silandic Andosol is rich in active aluminium forms, while the vitric Andosol has high amounts of crystalline iron and aluminium oxides. Sorption isotherms were determined by equilibrating at 293K soil samples with phosphate solutions of concentrations between 0 and 100 mg P L−1 in NaNO3; phosphate was determined by visible spectrophotometry in the equilibrium solution. To study desorption, the soil samples from the sorption experiment were equilibrated with 0.02 M NaNO3. The isotherms were adjusted to mathematical models. In almost all the concentration range, the adsorption of phosphate by the silandic Andosol was greater than 90% of the amount added, being lower in the vitric Andosol but always higher than 65%. The high sorption by the silandic Andosol is attributed to its richness in non-crystalline Fe and Al, while in the vitric Andosol crystalline iron species seem to play a relevant role in the adsorption. The sorption isotherms of both soils fitted to the Temkin model, the adjustment to the Langmuir or Freundlich models being unsatisfactory; throughout the range studied, the sorption increases with increasing phosphorus concentration, a maximum sorption is not predictable (as occurs when the sorption is adjusted to the Langmuir model). For an added P concentration of 100 mg L−1 (3.2 mmol L−1), the sorption is 47.7 µmol P g−1 in the silandic Andosol and 41.6 µmol P g−1 in the vitric Andosol. The desorption is low and the comparison of the sorption and desorption isotherms reveals a pronounced hysteresis, that is, the irreversibility of the sorption. The high phosphate sorption and its irreversibility are comparable to those published for other volcanic soils with high contents of allophane, active aluminium and free iron. The strong phosphate adsorption is a serious limiting factor for plant growth, which requires a careful management of phosphorus fertilization.


2015 ◽  
Vol 71 (12) ◽  
pp. 1875-1883 ◽  
Author(s):  
HyunJu Park ◽  
Duc Canh Nguyen ◽  
Choo-Ki Na

In this study, we investigated the removal of phosphate from aqueous solutions using (vinylbenzyl)-trimethylammonium chloride (VBTAC) grafted onto poly(ethylene terephthalate) (PET) fibers (PET-g-VBTAC). Batch-mode experiments were conducted using various contact times, initial phosphate concentrations, temperatures, pH values, and competing anions, to understand phosphate sorption onto PET-g-VBTAC. The phosphate sorption capacity of PET-g-VBTAC increased with increasing solution pH and was highest near pH 7. The equilibrium data fitted the Langmuir isotherm model well. The maximum sorption capacity (qm) of PET-g-VBTAC for phosphate was 55.6–56.0 mg/g at 25–45 °C. The sorption process followed a pseudo-second-order kinetic model. The obtained values of the mean free energy indicated that sorption of phosphate on PET-g-VBTAC occurs via ion exchange. Thermodynamic parameters, enthalpy change, entropy change, and Gibb's free energy, confirmed that phosphate sorption was spontaneous and endothermic. The adverse effects of competing anions on phosphate removal by PET-g-VBTAC were insignificant. These results demonstrate that PET-g-VBTAC effectively removes phosphate from aqueous solutions by ion exchange.


2016 ◽  
Vol 74 (5) ◽  
pp. 1069-1078 ◽  
Author(s):  
Mohammad Hossein Rasoulifard ◽  
Soghra Khanmohammadi ◽  
Azam Heidari

In the present study, we have used a simple and cost-effective removal technique by a commercially available Fe-Al-SiO2 containing complex material (hardened paste of Portland cement (HPPC)). The adsorbing performance of HPPC and modified HPPC with perlite for removal of cefixime from aqueous solutions was investigated comparatively by using batch adsorption studies. HPPC has been selected because of the main advantages such as high efficiency, simple separation of sludge, low-cost and abundant availability. A Taguchi orthogonal array experimental design with an OA16 (45) matrix was employed to optimize the affecting factors of adsorbate concentration, adsorbent dosage, type of adsorbent, contact time and pH. On the basis of equilibrium adsorption data, Langmuir, Freundlich and Temkin adsorption isotherm models were also confirmed. The results showed that HPPC and modified HPPC were both efficient adsorbents for cefixime removal.


2006 ◽  
Vol 3 (1) ◽  
pp. 65 ◽  
Author(s):  
Darren J. Akhurst ◽  
Graham B. Jones ◽  
Malcolm Clark ◽  
David McConchie

Environmental Context.Eutrophication of freshwater and marine ecosystems is a global problem, which is frequently linked to high phosphorus concentrations. The present study investigated the use of Bauxsol™, a modified bauxite refinery residue, to remove dissolved phosphate from water, and has shown that it can be used as a cost-effective adsorbent for treating phosphate-contaminated waters. The results provide water and environmental managers with a new technique for decreasing the phosphate loads in water and wastewater. Environmental benefits include improved water quality, minimisation of excessive plant growth, including potentially toxic blue green algae, and the utilisation of an industrial residue for environmental remediation. Abstract.Phosphate (PO43–) removal by Bauxsol™, a neutralised bauxite refinery residue, was investigated as a function of time, pH, ionic strength, adsorbent dosage, competing ions, and initial phosphate concentration. The results of adsorption and desorption studies indicate that adsorption of PO43– by Bauxsol™ is based on a ligand-exchange mechanism, although the low reversibility pH-independent desorption observed in acid-treated Bauxsol™ indicates a dominance of chemisorption. It was shown that PO43– adsorption onto both Bauxsol™ and acid-treated Bauxsol™ followed a Langmuir isotherm model, with adsorption capacities of 0.21 and 0.48 mmol g−1 at pH 9.0 and 5.2 respectively. Adsorption of PO43– by Bauxsol™ increased with decreasing pH, with maximum adsorption efficiencies obtained at pH 5.2 ± 0.1 (the lowest pH investigated), higher Bauxsol™ to initial phosphate concentration ratios, and increased time. Studies of the effects of competing ions on the adsorption of PO43– by Bauxsol™ indicated that adsorption decreased in the presence of HCO3− ions, whereas SO42–and Cl− ions had little effect, and Ca2+ and Mg2+ ions increased adsorption. These findings suggest that Bauxsol™ could be used as an efficient low-cost adsorbent for treating phosphate-contaminated waters.


2014 ◽  
Vol 567 ◽  
pp. 62-67 ◽  
Author(s):  
Mubin Zahari Nazirul ◽  
Chua Kok Hua ◽  
Lariyah Mohd Sidek

Alum sludge contained a large portion amount of the aluminum derived from the coagulation process in secondary stage water treatment. Alum sludge is discharge to the landfill and it can affect on disposal management. This study investigates the treatment of wastewater using the low-cost adsorption material and also an innovation in green technology for the preservation of the environment. This finding attempts to determine the effectiveness of dewatered water treatment alum sludge as media to remove pollutant (phosphate) from wastewater. The continuous flow test approach with constant speed allocate is being used in this study. Alum sludge was prepared in 2.36 mm sieve size in dry condition and the initial synthetic water concentration (phosphate solution) was set in increasing order 2.6 mg/L to 30.5 mg/L. The test was monitored over 30 days with constant flow rate. The results indicated removal phosphate in beginning of contact time at 30% - 90%. The maximum percentage removal is 91% - 98% in various condition. The dewatered alum sludge from water treatment plant has great potential as phosphate removal.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad Waqar Ashraf ◽  
Nidal Abulibdeh ◽  
Abdus Salam

Chrysoidine is a type of industrial azo dye and a well-known toxicant. Due to its good dyeing characteristics, it is widely used for dyeing leather, paper, feather, grass, wood, bamboo, etc. Hence, it is very important to remove or reduce its concentration below the contamination level in the waste line by using low-cost technologies. Sawdust is a plentiful material available very cheaply from sawmills and woodworks. Therefore, the present work was conducted to study sorption ability of both raw sawdust and chemically activated sawdust carbon on the removal of chrysoidine from the aqueous solutions. Adsorption isotherms of the dye on sawdust were determined and correlated with usual isotherm equations like Freundlich and Langmuir. Experimental results have shown that sawdust has a high adsorption efficiency, and the adsorption of chrysoidine followed Freundlich’s isotherm. Although raw sawdust proved to be slightly less efficient in comparison to chemically treated sawdust but in economic terms, raw sawdust is more cost-effective as the difference in the percent dye removal is less than the difference in the manufacturing costs. The influence of several parameters such as effect of temperature, adsorbent dose, adsorption time, etc., on the adsorption process was studied along with thermodynamic parameters such as enthalpy (ΔH°) and entropy (ΔS°).


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