A comparative study on phosphate removal from water using
            Phragmites australis
            biochars loaded with different metal oxides

Metal oxide-loaded biochars are a promising material to remove phosphate from polluted water to ultra-low concentrations. To facilitate preparing the metal oxide-loaded biochar with the best phosphate adsorption performance, five biochars loaded with Al, Ca, Fe, La and Mg oxides, respectively (Al-BC, Ca-BC, Fe-BC, La-BC and Mg-BC) were produced using Phragmites australis pretreated with 0.1 mol AlCl 3 , CaCl 2 , FeCl 3 , LaCl 3 and MgCl 2 , respectively, characterized, and phosphate adsorption kinetics and isotherms of the biochars were determined. The maximum phosphate adsorption capacities ( Q m ) of the biochars ranked as Al-BC (219.87 mg g −1 ) > Mg-BC (112.45 mg g −1 ) > Ca-BC (81.46 mg g −1 ) > Fe-BC (46.61 mg g −1 ) > La-BC (38.93 mg g −1 ). The time to reach the adsorption equilibrium ranked as La-BC (1 h) < Ca-BC (12 h) < Mg-BC (24 h) = Fe-BC (24 h) <Al-BC (greater than 72 h). Q m of Ca-BC, Fe-BC, La-BC and Mg-BC depend on the molar content of metals in the biochars. The small phosphate adsorption rate of Al-BC is due to the slow intra-particle diffusion of phosphate attributed to the undeveloped porosity and dispersed distribution of AlOOH crystals on the Al-BC surface. Mg-BC is suggested for phosphate removal from water considering adsorption rate and capacity. Al-BC is applicable when a long contact time is allowed, e.g. as a capping material to immobilize phosphate in lake sediments.

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Kinetic studies of phosphate adsorption onto construction solid waste (CSW)

Water Quality Research Journal ◽

10.2166/wqrjc.2014.013 ◽

2014 ◽

Vol 49 (4) ◽

pp. 307-318 ◽

Cited By ~ 4

Author(s):

C. Liu ◽

Y. Yang ◽

N. Wan

Keyword(s):

Solid Waste ◽

Low Cost ◽

Kinetic Studies ◽

Second Order ◽

Phosphate Removal ◽

Alkaline Condition ◽

Phosphate Adsorption ◽

Particle Diffusion ◽

Order Kinetic ◽

Intra Particle Diffusion

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.

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One-Pot Synthesis of Mesoporous MCM-41 with Different Functionalization Levels and their Adsorption Abilities to Phosphate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.476-478.1969 ◽

2012 ◽

Vol 476-478 ◽

pp. 1969-1973 ◽

Cited By ~ 2

Author(s):

Wei Ya Huang ◽

Jun Yang ◽

Yuan Ming Zhang

Keyword(s):

Removal Rate ◽

Langmuir Model ◽

Phosphate Concentration ◽

Phosphate Removal ◽

Phosphate Adsorption ◽

Experiment Data ◽

Sorption Equilibrium ◽

One Pot ◽

Adsorption Capacities ◽

Mcm 41

Ethylenediamine (EDA) functionalized mesoporous MCM-41 particles displaying various functionalization levels have been prepared by one-pot method. The prepared samples were treated with Fe(III) to form cationic complexes inside MCM-41 pores (MCM-41-NN-Fe-x%, x=10, 20 and 30) for trapping phosphate from water. The prepared adsorbents were characterized by XRD, BET, TGA and elemental analysis, and their phosphate adsorption performances were studied. The results showed that the phosphate removal rate of all the prepared adsorbents were higher than 95% at the initial phosphate concentration of 2 ppm. Additionally, the Langmuir model was used to simulate the sorption equilibrium, and the results indicated that the experiment data agreed well with the Langmuir model. The maximum adsorption capacities calculated from the Langmuir model increased with the increase of diamino loadings in adsorbents, and the maximum adsorption capacities of MCM-41-NN-Fe-30% was 52.5 mg/g.

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Efficient capture of phosphate from aqueous solution using acid activated akadama clay and mechanisms analysis

Water Science & Technology ◽

10.2166/wst.2018.441 ◽

2018 ◽

Vol 78 (7) ◽

pp. 1603-1614 ◽

Cited By ~ 5

Author(s):

Ying Wang ◽

Hui He ◽

Nan Zhang ◽

Kazuya Shimizu ◽

Zhongfang Lei ◽

...

Keyword(s):

Aqueous Solution ◽

Ph Effect ◽

Phosphate Removal ◽

Phosphate Adsorption ◽

Order Kinetic ◽

Negative Effects ◽

Initial Ph ◽

Intra Particle Diffusion ◽

Langmuir Isotherm Model ◽

Ph Range

Abstract In this study, akadama clay, a kind of volcano ash, was activated with sulfuric acid and then evaluated for the adsorption of phosphate from aqueous solution via batch experiments. The effects of adsorbent dose, initial pH and coexisting anions on phosphate removal by natural akadama clay and acid-activated akadama clay were investigated. Based on the pH effect, the modified adsorbent could efficiently capture phosphate over a wider pH range of 3.00–6.00 than natural akadama clay. Competitive anions showed negative effects on the phosphate adsorption, especially citrate and carbonate. The adsorption process followed the pseudo-second-order kinetic equation and the intra-particle diffusion. Langmuir isotherm model was found to fit the data better than Freundlich model, and the maximum adsorption capacities of phosphate onto the natural akadama clay and acid-activated akadama clay were 5.88 and 9.19 mg/g, respectively. Furthermore, thermodynamic studies confirmed that the adsorption of acid-activated akadama clay was a spontaneous process. The mechanisms of phosphate adsorption on the clay could be ascribed to electrostatic attraction and ligand exchange. These results suggest that after modification, acid-activated akadama clay could be used as a promising adsorbent for phosphate removal from wastewater in real application and then further used as fertilizers.

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Study on an effective industrial waste-based adsorbent for the adsorptive removal of phosphorus from wastewater: equilibrium and kinetics studies

Water Science & Technology ◽

10.2166/wst.2016.021 ◽

2016 ◽

Vol 73 (8) ◽

pp. 1891-1900 ◽

Cited By ~ 4

Author(s):

Ruzhen Xie ◽

Yao Chen ◽

Ting Cheng ◽

Yuguo Lai ◽

Wenju Jiang ◽

...

Keyword(s):

Industrial Waste ◽

Phosphate Removal ◽

Phosphate Adsorption ◽

Order Kinetic ◽

Solution Ph ◽

Before And After ◽

Equilibrium And Kinetics ◽

Equilibrium Data ◽

Intra Particle Diffusion ◽

Ph Range

In this work, an effective adsorbent for removing phosphate from aqueous solution was developed from modifying industrial waste — lithium silica fume (LSF). The characterization of LSF before and after modification was investigated using an N2 adsorption–desorption technique (Brunauer–Emmett–Teller, BET), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Studies were conducted to investigate the effect of adsorbent dose, initial solution pH, contact time, phosphate concentration, and temperature on phosphate removal using this novel adsorbent. The specific surface area for modified LSF (LLSF) is 24.4024 m2/g, improved 69.8% compared with unmodified LSF. XRD result suggests that the lanthanum phosphate complex was formed on the surface of LLSF. The maximum phosphate adsorption capacity was 24.096 mg P/g for LLSF, and phosphate removal was favored in the pH range of 3–8. The kinetic data fitted pseudo-second-order kinetic equation, intra-particle diffusion was not the only rate controlling step. The adsorption isotherm results illustrated that the Langmuir model provided the best fit for the equilibrium data. The change in free energy (△G0), enthalpy (△H0) and entropy (△S0) revealed that the adsorption of phosphate on LLSF was spontaneous and endothermic. It was concluded that by modifying with lanthanum, LSF can be turned to be a highly efficient adsorbent in phosphate removal.

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Preparation, Characterization, and Application of Novel Ferric Oxide-Amine Material for Removal of Nitrate and Phosphate in Water

Journal of Chemistry ◽

10.1155/2020/8583543 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Trung Thanh Nguyen ◽

Tri Thich Le ◽

Phuoc Toan Phan ◽

Nhat Huy Nguyen

Keyword(s):

Ferric Oxide ◽

Exchange Resin ◽

Xrd Analysis ◽

Ion Exchange Resin ◽

Phosphate Removal ◽

Phosphate Adsorption ◽

Practical Applications ◽

Adsorption Capacities ◽

Adsorption Temperature ◽

Potential Use

Ferric oxide-amine material was synthesized and applied as a novel adsorbent for nitrate and phosphate removal from aqueous solution. The properties of ferric oxide-amine were examined using TGA, FTIR, BET, SEM, EDX, SEM-mapping, and XRD analysis. The results showed that the adsorption using ferric oxide-amine material reached equilibrium after 30 and 60 min for nitrate and phosphate, respectively. The highest nitrate and phosphate adsorption capacities were 131.4 mg nitrate/g at pH 5-6 and 42.1 mg phosphate/g at pH 6. The effects of adsorbent dosage, initial concentrations of nitrate and phosphate, and adsorption temperature were also investigated. Among the three adsorbents of ferric oxide-amine, ferric oxide, and Akualite A420 ion exchange resin, ferric oxide-amine material had the highest adsorption capacity for nitrate and phosphate removal. These results suggest a great potential use of ferric oxide-amine material for water treatment in practical applications.

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Treatment of tunnel wash water and implications for its disposal

Water Science & Technology ◽

10.2166/wst.2014.113 ◽

2014 ◽

Vol 69 (10) ◽

pp. 2029-2035 ◽

Cited By ~ 2

Author(s):

M. Hallberg ◽

G. Renman ◽

L. Byman ◽

G. Svenstam ◽

M. Norling

Keyword(s):

Traffic Safety ◽

Urban Areas ◽

Suspended Solids ◽

Treatment Plant ◽

Particulate Material ◽

Wash Water ◽

Polluted Water ◽

Solids Concentration ◽

Low Concentrations ◽

Road Tunnels

The use of road tunnels in urban areas creates water pollution problems, since the tunnels must be frequently cleaned for traffic safety reasons. The washing generates extensive volumes of highly polluted water, for example, more than fivefold higher concentrations of suspended solids compared to highway runoff. The pollutants in the wash water have an affinity for particulate material, so sedimentation should be a viable treatment option. In this study, 12 in situ sedimentation trials were carried out on tunnel wash water, with and without addition of chemical flocculent. Initial suspended solids concentration ranged from 804 to 9,690 mg/L. With sedimentation times of less than 24 hours and use of a chemical flocculent, it was possible to reach low concentrations of suspended solids (<15 mg/L), PAH (<0.1 μg/L), As (<1.0 μg/L), Cd (<0.05 μg/L), Hg (<0.02 μg/L), Fe (<200 μg/L), Ni (<8 μg/L), Pb (<0.5 μg/L), Zn (<60 μg/L) and Cr (<8 μg/L). Acute Microtox® toxicity, mainly attributed to detergents used for the tunnel wash, decreased significantly at low suspended solids concentrations after sedimentation using a flocculent. The tunnel wash water did not inhibit nitrification. The treated water should be suitable for discharge into recipient waters or a wastewater treatment plant.

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Phosphorus Release and Adsorption Properties of Polyurethane–Biochar Crosslinked Material as a Filter Additive in Bioretention Systems

Polymers ◽

10.3390/polym13020283 ◽

2021 ◽

Vol 13 (2) ◽

pp. 283

Author(s):

Yike Meng ◽

Yuan Wang ◽

Chuanyue Wang

Keyword(s):

Removal Rate ◽

Phosphorus Release ◽

Phosphate Adsorption ◽

Stormwater Treatment ◽

Isothermal Adsorption ◽

Phosphorus Pollution ◽

Adsorption Capacities ◽

Saturated Water Content ◽

Phosphate Treatment ◽

Potential Use

Bioretention systems are frequently employed in stormwater treatment to reduce phosphorus pollution and prevent eutrophication. To enhance their efficiency, filter additives are required but the currently used traditional materials cannot meet the primary requirements of excellent hydraulic properties as well as outstanding release and adsorption capacities at the same time. In this research, a polyurethane-biochar crosslinked material was produced by mixing the hardwood biochar (HB) with polyurethane to improve the performance of traditional filter additives. Through basic parameter tests, the saturated water content of polyurethane-biochar crosslinked material (PCB) was doubled and the permeability coefficient of PCB increased by two orders of magnitude. Due to the polyurethane, the leaching speed of phosphorus slowed down in the batching experiments and fewer metal cations leached. Moreover, PCB could adsorb 93–206 mg/kg PO43− at a typical PO43− concentration in stormwater runoff, 1.32–1.58 times more than HB, during isothermal adsorption experiments. In the simulating column experiments, weaker hydropower reduced the PO43− leaching quantities of PCB and had a stable removal rate of 93.84% in phosphate treatment. This study demonstrates the potential use of PCB as a filter additive in a bioretention system to achieve hydraulic goals and improve phosphate adsorption capacities.

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

Materials ◽

10.3390/ma14051312 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1312

Author(s):

Dereje Tadesse Mekonnen ◽

Esayas Alemayehu ◽

Bernd Lennartz

Keyword(s):

Aqueous Solutions ◽

Low Income ◽

Low Cost ◽

Volcanic Rocks ◽

Phosphate Removal ◽

Phosphate Adsorption ◽

Adsorptive Capacity ◽

Batch Adsorption ◽

Order Kinetic ◽

Adsorptive Removal

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.

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Microwave Sensors for In Situ Monitoring of Trace Metals in Polluted Water

Sensors ◽

10.3390/s21093147 ◽

2021 ◽

Vol 21 (9) ◽

pp. 3147

Author(s):

Ilaria Frau ◽

Stephen Wylie ◽

Patrick Byrne ◽

Patrizia Onnis ◽

Jeff Cullen ◽

...

Keyword(s):

Trace Metals ◽

In Situ Monitoring ◽

Polluted Water ◽

Pollution Level ◽

Mining Areas ◽

Low Concentrations ◽

The Uk ◽

Microwave Sensors ◽

Immediate Response

Thousands of pollutants are threatening our water supply, putting at risk human and environmental health. Between them, trace metals are of significant concern, due to their high toxicity at low concentrations. Abandoned mining areas are globally one of the major sources of toxic metals. Nowadays, no method can guarantee an immediate response for quantifying these pollutants. In this work, a novel technique based on microwave spectroscopy and planar sensors for in situ real-time monitoring of water quality is described. The sensors were developed to directly probe water samples, and in situ trial measurements were performed in freshwater in four polluted mining areas in the UK. Planar microwave sensors were able detect the water pollution level with an immediate response specifically depicted at three resonant peaks in the GHz range. To the authors’ best knowledge, this is the first time that planar microwave sensors were tested in situ, demonstrating the ability to use this method for classifying more and less polluted water using a multiple-peak approach.

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