Adsorptive removal of phosphate from aqueous solutions using lead–zinc tailings

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.

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.


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 3 (1) ◽  
pp. 208-220
Author(s):  
Sara Jamaliniya ◽  
O. D. Basu ◽  
Saumya Suresh ◽  
Eustina Musvoto ◽  
Alexis Mackintosh

Abstract A renewable, green activated carbon made from sucrose (sugar) was compared with traditional bituminous coal-based granular activated carbon (GAC). Single and multi-component competitive adsorption of nitrate and phosphate from water was investigated. Langmuir and Freundlich isotherm models were fitted to data obtained from the nitrate and phosphate adsorption experiments. Nitrate adsorption fits closely to either Freundlich or Langmuir model for sucrose activated carbon (SAC) and GAC with a Langmuir adsorption capacity of 7.98 and 6.38 mg/g, respectively. However, phosphate adsorption on SAC and GAC demonstrated a selective fit with the Langmuir model with an adsorption capacity of 1.71 and 2.07 mg/g, respectively. Kinetic analysis demonstrated that adsorption of nitrate and phosphate follow pseudo-second-order kinetics with rate constant values of 0.061 and 0.063 g/(mg h), respectively. Competitive studies between nitrate and phosphate were demonstrated in preferential nitrate removal with GAC and preferential phosphate removal with SAC. Furthermore, nitrate and phosphate removals decreased from 75% removal to 35% removal when subject to multi-component solutions, which highlights the need for adsorption analysis in complex systems. Overall, SAC proved to be competitive with GAC in the removal of inorganic contaminants and may represent a green alternative to coal-based activated carbon.


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.


2016 ◽  
Vol 24 (3) ◽  
pp. 319-332 ◽  
Author(s):  
Mengxue Li ◽  
Jianyong Liu ◽  
Yunfeng Xu ◽  
Guangren Qian

Phosphorus removal from wastewater is important for eutrophication control of water bodies. Metal oxides and metal hydroxides have always been developed and investigated for phosphorus removal, because of their abundance, low cost, environmental friendliness, and chemically stability. This paper presents a comparative review of the literature on the preparation methods, adsorption behaviors, adsorption mechanisms, and the regeneration of metal (hydr)oxides (e.g., Fe, Zn, Al, etc.) with regard to phosphate removal. The contrasting results showed that metal hydroxides could offer an effective and economic alternative to metal oxides, because of their cost–benefit synthesis methods, higher adsorption capacities, and shorter adsorption equilibrium times. However, the specific surface area of metal oxides is larger than that of metal hydroxides because of the calcination process. Metal oxides with a higher pH at the zero point of charge have wider optimal adsorption pH ranges than metal hydroxides because of their surface precipitation in alkaline solutions. The regeneration of metal oxides using acids, bases, and salts and that of metal hydroxides using acids and bases has been critically examined. Further research on uniform metal (hydr)oxides with small particle size, high stabilities, low cost, and that are easily regenerated with promising desorbents are proposed. In addition, quantitative mechanism study and application in continuous-mode column trials are also suggested.


2020 ◽  
Vol 81 (12) ◽  
pp. 2617-2633
Author(s):  
Wondwosen Kebede Biftu ◽  
Kunta Ravindhranath

Abstract Nano particles of ZrO2 of average size 10.91 nm are successfully synthesized via green routes from a solvent blend of water and ethylene glycol (4:1 v/v). Bio-extract of seeds of Sapindus plant is employed as stabilizing and/or capping agent and homogeneous method of precipitation is adopted to generate the precipitating agent. The nZrO2 particles are immobilized in aluminum alginate beads (nZrO2-Al- alig). Nano-ZrO2 and beads are investigated as adsorbents for the extraction of phosphate from water. The controlling physicochemical parameters are studied for the maximum phosphate removal using simulate water. The optimum conditions are: pH: 7; sorbent dosage: 0.1 g/100 mL for nZrO2 and 0.08 g/100 mL for beads; equilibration time: 30 min.for nZrO2 and 35 min for beads; initial phosphate concentration: 50 mg/L; temperature: 30 ± 1 °C; 300 rpm. The adsorption capacities are: 126.2 mg/g for nZrO2 and 173.0 mg/g for ‘nZrO2-Al- alig’ and they are higher than many reported in literature. The beads, besides facilitating the easy filtration, are exhibiting enhanced cumulative phosphate-adsorption nature of nanoZrO2 and Al-alginate. X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray (EDX) investigations are employed in characterizing the adsorbents. Of the various isotherm models analyzed to assess the nature of adsorption, Freundlich model provides the best correlation (R2 = 0.99 for nZrO2 and R2 = 0.99 for ‘nZrO2-Al-alig’), indicating the heterogeneous and multi-layered adsorption process. Thermodynamic studies reveal the endothermic and spontaneous nature of sorption. Pseudo-second-order model of kinetics describes the adsorption well. Spent adsorbents can be regenerated with marginal loss of adsorption capacity until five cycles. The sorbents are successfully applied to remove phosphate from polluted lake water samples.


2020 ◽  
Vol 10 (12) ◽  
Author(s):  
Tze Ling Kua ◽  
Muhammad Raziq Rahimi Kooh ◽  
Muhammad Khairud Dahri ◽  
Nur Afiqah Hazirah Mohamad Zaidi ◽  
YieChen Lu ◽  
...  

AbstractIpomoea aquatica (IA) was investigated for its potential as a low-cost adsorbent to remove toxic methyl violet 2B (MV2B) dye in aqueous solutions. Optimising parameters such as the effects of contact time, medium pH and ionic strength (using NaCl, NaNO3, KCl and KNO3) were investigated. The results indicated that 150 min were sufficient for the adsorption to reach an equilibrium state and no adjustment of pH medium was necessary. Batch adsorption experiments such as adsorption isotherm, thermodynamics and kinetics were investigated and the experimental isotherm data were fitted to six isotherm models, namely Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Redlich-Peterson and Sips, with the latter being the best-fit isotherm model showing maximum adsorption capacity (qmax) of 267.9 mg g−1. Thermodynamics studies indicated adsorption of MV2B to be exothermic in nature, occurring spontaneously. The kinetics was best described by the pseudo-second-order model. Regeneration of IA pointed to its reusability, maintaining high adsorption capacity even up until Cycle 5 when treated with acid (HCl) and base (NaOH). Functional groups such as hydroxyl and amine groups which could be involved in the adsorption of MV2B were determined using FTIR spectroscopy, and the point of zero charge of IA was found to be at pH 6.81.


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.


e-Polymers ◽  
2017 ◽  
Vol 17 (6) ◽  
pp. 501-506 ◽  
Author(s):  
Soo-Kwan Kim ◽  
Jun-Hyun Mo ◽  
Jae-Yeop Kim ◽  
Kwang-Suk Jang

AbstractThis study demonstrates a simple two-step post-treatment method for improving the thermoelectric power factor of low-cost poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) films. The dry re-dispersible PEDOT:PSS pellets are cost-effective, however, they exhibit extremely low thermoelectric performance. On treating with ethylene glycol followed by hydrazine, the power factor of the PEDOT:PSS films increased from 0.0632±0.0097 μW m−1K−2 to 13.3±1.5 μW m−1K−2. The enhancement might be attributed to the effective removal of the free, non-complexed PSS chains and fine control of the oxidation level of PEDOT by the two-step post-treatment.


2002 ◽  
Vol 46 (9) ◽  
pp. 297-302 ◽  
Author(s):  
S.M. Lee ◽  
B.J. Choi ◽  
K.H. Kim

There is a need for developing low cost, easily and abundantly available, yet efficient, adsorbents for the removal of phosphates during the tertiary treatment of wastewater. The wasted sludge from a cuttlefish processing factory prepared on a laboratory scale has been used to evaluate its performance for phosphate adsorption. The material has been shown to be a good alternative adsorbent. As much as 90% phosphate removal by the prepared sludge is possible in about 20 h under the test conditions. Phosphate removal is seen to increase with decreasing adsorbent particle size, increasing the relative concentration of phosphate to sludge and increasing adsorbent dose. Models for predicting phosphate removal incorporate operational variables such as the ratio of phosphate to wasted material and adsorbent dose. These models also manifest high values of the correlation coefficients. Calcium phosphate precipitation in the present experimental system is not a significant phosphate removal mechanism.


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