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Jurado-Davila IV, Schneider IAH, Estumano D, Amaral Féris L. Phosphate removal using dolomite modified with ultrasound: mathematical and experimental analysis. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2023; 58:469-482. [PMID: 37005870 DOI: 10.1080/10934529.2023.2196928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 03/11/2023] [Accepted: 03/18/2023] [Indexed: 06/19/2023]
Abstract
We studied the dolomite modified using an ultrasound bath and its application in phosphate removal. The modification was applied to improve the physicochemical properties of the dolomite and then to enhance its suitability as an adsorbent solid. The settings for analyzing the adsorbent modification were bath temperature and sonication time. The modified dolomite was characterized by electron microscopy, N2 adsorption/desorption, pore size, and X-ray diffraction. To grasp the pollutant's adsorption mechanism more precisely, we used experimental research and mathematical model analysis. Design of Experiments was conducted to determine the ideal circumstances. In addition, the Bayesian method of Markov Chain Monte Carlo was used to estimate the isotherm and kinetic model parameters. A thermodynamic study was done to investigate the adsorption mechanism. Results show that the surface area of the modified dolomite was greater, enhancing its adsorption properties. To remove more than 90% of the phosphate, the optimal operational parameters for the adsorption were pH 9, 1.77 g of adsorbent mass, and 55 minutes of contact time. The pseudo-first-order, Redlich-Peterson and Sips models presented a good fit to the experimental data. Thermodynamics suggested a spontaneous and endothermic process. The mechanism suggested that physisorption and chemisorption could be involved in phosphate removal.
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Patil MP, Woo HE, Lee IC, Nakashita S, Kim K, Kim JO, Kim K. A microcosm study of microbial community profiles during sediment remediation using pyrolyzed oyster shells. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115229. [PMID: 35544980 DOI: 10.1016/j.jenvman.2022.115229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/27/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
The accumulation of organic and inorganic components in sediments leads to a deterioration in the environment and an imbalance in the coastal ecosystem. Currently, capping is the most effective technology for remediating polluted sediment and restoring ecosystems. A microcosm experiment was designed using pyrolyzed oyster shell (POS). These were mixed in with coastal sediment or added as a capping layer. The results showed that POS effectively decreased pollutants, including PO4-P and NH4-N. Metagenomics analysis was performed using 16S rRNA gene sequencing and the most abundant phyla identified in the POS treated and untreated sediments were Proteobacteria, followed by Firmicutes, Bacteroidetes, Chloroflexi, Fusobacteria, Nitrospirae, and Spirochaetes. The relative abundance of Proteobacteria members of the Class Gammaproteobacteria significantly increased, but Deltaproteobacteria gradually decreased throughout the experiment in POS-covered sediment. This suggests that the POS effectively promoted a shift from anaerobic to facultative anaerobic or aerobic microbial communities in the sediment. Dominant species of facultative anaerobic or microaerophilic bacteria from the order Chromatiales and phylum Nitrospirae were observed in the POS-covered sediment. Based on these study results, it can be concluded that POS is an effective covering material for sediment remediation and restores the microbial communities in sediments.
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Affiliation(s)
- Maheshkumar Prakash Patil
- Industry-University Cooperation Foundation, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan, 48513, Republic of Korea
| | - Hee-Eun Woo
- Department of Ocean Engineering, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan, 48513, Republic of Korea
| | - In-Cheol Lee
- Department of Ocean Engineering, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan, 48513, Republic of Korea
| | - Shinya Nakashita
- Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima, 739-8527, Hiroshima, Japan
| | - Kyeongmin Kim
- Graduate School of Advanced Science and Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima, 739-8527, Hiroshima, Japan; Coastal and Estuarine Sediment Dynamics Group, Port and Airport Research Institute, 3-1-1 Nagase, Yokosuka, 239-0826, Kanagawa, Japan
| | - Jong-Oh Kim
- Department of Microbiology, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan, 48513, Republic of Korea; School of Marine and Fisheries Life Science, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan, 48513, Republic of Korea.
| | - Kyunghoi Kim
- Department of Ocean Engineering, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan, 48513, Republic of Korea.
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Jeong I, Nakashita S, Hibino T, Kim K. Effect of sediment deposition on phosphate and hydrogen sulfide removal by granulated coal ash in coastal sediments. MARINE POLLUTION BULLETIN 2022; 179:113679. [PMID: 35489092 DOI: 10.1016/j.marpolbul.2022.113679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/17/2022] [Accepted: 04/18/2022] [Indexed: 06/14/2023]
Abstract
Granulated coal ash (GCA) is a strong in-situ capping material for removing PO4-P and H2S-S in contaminated coastal sediments. Although GCA performance is weakened by sediment deposition, related research is rare. To evaluate sediment deposition effects on PO4-P and H2S-S removal by GCA, GCA was placed on the top of sediment (C-GCA), was partially mixed with sediment (M-GCA), and was fully covered by sediment (N-GCA). Effective PO4-P and H2S-S removal from sediments occurred in the order of C-GCA > M-GCA > N-GCA. C-GCA and M-GCA significantly decreased PO4-P and H2S-S concentrations by 84- 90% and 100%, respectively, through calcium phosphate and iron sulfide precipitation. N-GCA was less effective in PO4-P and H2S-S removal than the control after 2.5 months, as fine sediment particles blocked the GCA pores, decreasing calcium and iron elution. The results provide a better understanding of how sediment deposition negatively impacted GCA performance.
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Affiliation(s)
- Ilwon Jeong
- Department of Ocean Engineering, Pukyong National University, Busan 48513, Republic of Korea.
| | - Shinya Nakashita
- Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Tadashi Hibino
- Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
| | - Kyunghoi Kim
- Department of Ocean Engineering, Pukyong National University, Busan 48513, Republic of Korea.
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Jeong I, Kim K. Utilizing a granulated coal bottom ash and oyster shells for nutrient removal in eutrophic sediments. MARINE POLLUTION BULLETIN 2022; 177:113549. [PMID: 35303632 DOI: 10.1016/j.marpolbul.2022.113549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/07/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Various in-situ capping materials have been studied to remediate contaminated sediments for sustaining a healthy ecosystem in a coastal area. We developed Granulated coal bottom ash and oyster shells (GBO) with different mixing ratios of OS. Pyrolyzed and grounded coal bottom ash and oyster shells were used to produce GBO, which the main chemical elements were analogous to cement. The nutrient-removal abilities of GBO were evaluated through long-term mesocosm experiments. It was found that GBO was an effective in-situ capping material for remediation of eutrophic coastal sediments, decreasing PO4-P and SiO2-Si concentrations in pore water by 88.4% and 56.5%, respectively. The most efficient mixing ratio of coal bottom ash and oyster shells was at a weight ratio of 1:1 for PO4-P and SiO2-Si removal.
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Affiliation(s)
- Ilwon Jeong
- Department of Ocean Engineering, Pukyong National University, Busan 48513, Republic of Korea
| | - Kyunghoi Kim
- Department of Ocean Engineering, Pukyong National University, Busan 48513, Republic of Korea.
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Adsorptive Removal of Phosphate from Aqueous Solutions Using Low-Cost Volcanic Rocks: Kinetics and Equilibrium Approaches. MATERIALS 2021; 14:ma14051312. [PMID: 33803351 PMCID: PMC7967176 DOI: 10.3390/ma14051312] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 01/09/2023]
Abstract
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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Removal of Phosphate Ions from Aqueous Solutions by Adsorption onto Leftover Coal. WATER 2020. [DOI: 10.3390/w12051381] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
High loadings of wastewater with phosphors (P) require purification measures, which can be challenging to realize in regions where the technical and financial frame does not allow sophisticated applications. Simple percolation devices employing various kinds of adsorbents might be an alternative. Here, we investigated the application of leftover coal, which was collected from Ethiopian coal mining areas, as an adsorbent for the removal of phosphate from aqueous solutions in a classical slurry batch set-up. The combined effects of operational parameters such as contact time, initial concentration, and solution pH on P retention efficiency was studied employing the Response Surface Methodology (RSM). The maximum phosphate adsorption (79% removal and 198 mg kg−1 leftover coal) was obtained at a contact time of 200 min, an initial phosphate concentration of 5 mg/L, and a solution pH of 2.3. The Freundlich isotherm was fitted to the experimental data. The pseudo second-order equation describes the experimental data well, with a correlation value of R2 = 0.99. The effect of temperature on the adsorption reveals that the process is exothermic. The results demonstrate that leftover coal material could potentially be applied for the removal of phosphate from aqueous media, but additional testing in a flow-through set-up using real wastewater is required to draw definite conclusions.
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Kim K, Kim K. Remediation of contaminated intertidal sediment by increasing permeability using active capping material. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 253:109769. [PMID: 31675593 DOI: 10.1016/j.jenvman.2019.109769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 10/22/2019] [Accepted: 10/22/2019] [Indexed: 06/10/2023]
Abstract
A novel approach for the remediation of clayey sediment in intertidal zones was proposed, which entails increasing the soil permeability using an active capping agent. The agent, granulated coal ash (GCA), was developed using the granulation processes for coal fly ash. The GCA increased the permeability coefficient of the sediment by seven times, changing its the properties from a typical clayey silt to that of silt, according to the soil classification standards based on permeability coefficient. Increased permeability was attributed to Ca2+ ions, and adsorbed Na+ was immediately discharged, leading to a decrease in the sodium adsorption ratio. The activated flow of pore water stimulated nutrient loadings; PO4-P and NH4-N loads decreased by 55% and 44%, respectively. The GCA increased the dissolved oxygen by 1.8 mg/L and increased the redox potential in pore water from -370 to -306 mV vs. Ag/AgCl. According to the results presented in this study, active capping with GCA to increase soil permeability is a novel and promising technology for reducing the nutrient loads and increasing the oxidation of contaminated clayey sediment in intertidal zones.
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Affiliation(s)
- Kyeongmin Kim
- Graduate School of Engineering, Hiroshima University, Hiroshima, Japan; Department of Ocean Engineering, Pukyong National University, Busan, Republic of Korea
| | - Kyunghoi Kim
- Department of Ocean Engineering, Pukyong National University, Busan, Republic of Korea.
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Wang Y, Yu Y, Li H, Shen C. Comparison study of phosphorus adsorption on different waste solids: Fly ash, red mud and ferric-alum water treatment residues. J Environ Sci (China) 2016; 50:79-86. [PMID: 28034434 DOI: 10.1016/j.jes.2016.04.025] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 03/31/2016] [Accepted: 04/05/2016] [Indexed: 06/06/2023]
Abstract
The adsorption of phosphorus (P) onto three industrial solid wastes (fly ash, red mud and ferric-alum water treatment residual (FAR)) and their modified materials was studied systematically via batch experiments. Compared with two natural adsorbents (zeolite and diatomite), three solid wastes possessed a higher adsorption capacity for P because of the higher Fe, Al and Ca contents. After modification (i.e., the fly ash and red mud modified by FeCl3 and FARs modified by HCl), the adsorption capacity increased, especially for the modified red mud, where more Fe bonded P was observed. The P adsorption kinetics can be satisfactorily fitted using the pseudo-second-order model. The Langmuir model can describe well the P adsorption on all of the samples in our study. pH and dissolved organic matter (DOM) are two important factors for P adsorption. Under neutral conditions, the maximum adsorption amount on the modified materials was observed. With the deviation from pH7, the adsorption amount decreased, which resulted from the change of P species in water and surface charges of the adsorbents. The DOM in water can promote P adsorption, which may be due to the promotion effects of humic-Fe(Al) complexes and the pH buffer function exceeds the depression of competitive adsorption.
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Affiliation(s)
- Ying Wang
- School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Yange Yu
- School of Environment, Beijing Normal University, Beijing 100875, China
| | - Haiyan Li
- Beijing Engineering Research Center of Sustainable Urban Sewage System Construction and Risk Control, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
| | - Chanchan Shen
- School of Environment, Beijing Normal University, Beijing 100875, China
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Yamamoto H, Yamamoto T, Mito Y, Asaoka S. Numerical evaluation of the use of granulated coal ash to reduce an oxygen-deficient water mass. MARINE POLLUTION BULLETIN 2016; 107:188-205. [PMID: 27143344 DOI: 10.1016/j.marpolbul.2016.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 04/01/2016] [Accepted: 04/01/2016] [Indexed: 06/05/2023]
Abstract
Granulated coal ash (GCA), which is a by-product of coal thermal electric power stations, effectively decreases phosphate and hydrogen sulfide (H2S) concentrations in the pore water of coastal marine sediments. In this study, we developed a pelagic-benthic coupled ecosystem model to evaluate the effectiveness of GCA for diminishing the oxygen-deficient water mass formed in coastal bottom water of Hiroshima Bay in Japan. Numerical experiments revealed the application of GCA was effective for reducing the oxygen-deficient water masses, showing alleviation of the DO depletion in summer increased by 0.4-3mgl(-1). The effect of H2S adsorption onto the GCA lasted for 5.25years in the case in which GCA was mixed with the sediment in a volume ratio of 1:1. The application of this new GCA-based environmental restoration technique could also make a substantial contribution to form a recycling-oriented society.
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Affiliation(s)
- Hironori Yamamoto
- FUKKEN Co. Ltd., 2-10-11 Hikarimachi, Higashi-ku, Hiroshima-shi, Hiroshima 732-0052, Japan.
| | - Tamiji Yamamoto
- Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima-shi 739-8528, Japan
| | - Yugo Mito
- FUKKEN Co. Ltd., 2-10-11 Hikarimachi, Higashi-ku, Hiroshima-shi, Hiroshima 732-0052, Japan
| | - Satoshi Asaoka
- Research Center for Inland Seas, Kobe University, 5-1-1 Fukaeminami, Higashinada-ku, Kobe-shi 658-0022, Japan
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Wang D, Chen N, Yu Y, Hu W, Feng C. Investigation on the adsorption of phosphorus by Fe-loaded ceramic adsorbent. J Colloid Interface Sci 2016; 464:277-84. [DOI: 10.1016/j.jcis.2015.11.039] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/18/2015] [Indexed: 11/30/2022]
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Granulated Coal Ash – used Method for Remediation of Organic Matter Enriched Coastal Sediments. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.proeng.2015.08.297] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kim K, Hibino T, Yamamoto T, Hayakawa S, Mito Y, Nakamoto K, Lee IC. Field experiments on remediation of coastal sediments using granulated coal ash. MARINE POLLUTION BULLETIN 2014; 83:132-137. [PMID: 24759507 DOI: 10.1016/j.marpolbul.2014.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/31/2014] [Accepted: 04/02/2014] [Indexed: 06/03/2023]
Abstract
Field experiments were carried out to evaluate the effect of Granulated Coal Ash (GCA) on remediation of coastal sediments in terms of removing phosphates and hydrogen sulfide. Phosphate concentrations in the sediment were kept below 0.2 mg/l after the application of GCA, whereas those in the control sites increased up to 1.0 mg/l. The concentration of hydrogen sulfide in the sediment was maintained at almost zero in the experimental sites (GCA application sites) for over one year, whereas it ranged 0.1-2.4 mg S L(-1) in control sites. Meanwhile, individual number of benthos increased in the experimental sites by several orders of magnitude compared to the control sites. The major process involved in hydrogen sulfide removal by GCA was thought to be the increase in pH, which suppresses hydrogen sulfide formation. From our findings, we concluded that GCA is an effective material for remediating organically enriched coastal sediment.
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Affiliation(s)
- Kyunghoi Kim
- Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan.
| | - Tadashi Hibino
- Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
| | - Tamiji Yamamoto
- Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
| | - Shinjiro Hayakawa
- Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
| | - Yugo Mito
- Fukken Co., Ltd., Hiroshima 732-0052, Japan
| | - Kenji Nakamoto
- Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
| | - In-Cheol Lee
- Department of Ocean Engineering, Pukyong National University, 45, Yongso-ro, Nam-Gu, Busan 608-737, Republic of Korea
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Wang Z, Shi M, Li J, Zheng Z. Influence of moderate pre-oxidation treatment on the physical, chemical and phosphate adsorption properties of iron-containing activated carbon. J Environ Sci (China) 2014; 26:519-528. [PMID: 25079263 DOI: 10.1016/s1001-0742(13)60440-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/14/2013] [Accepted: 05/15/2013] [Indexed: 06/03/2023]
Abstract
A novel adsorbent based on iron oxide dispersed over activated carbon (AC) were prepared, and used for phosphate removal from aqueous solutions. The influence of pre-oxidation treatment on the physical, chemical and phosphate adsorption properties of iron-containing AC were determined. Two series of ACs, non-oxidized and oxidized carbon modified by iron (denoted as AC-Fe and AC/O-Fe), resulted in a maximum impregnated iron of 4.03% and 7.56%, respectively. AC/O-Fe showed 34.0%-46.6% higher phosphate removal efficiency than the AC-Fe did. This was first attributed to the moderate pre-oxidation of raw AC by nitric acid, achieved by dosing Fe(II) after a pre-oxidation, to obtain higher iron loading, which is favorable for phosphate adsorption. Additionally, the in-situ formed active site on the surface of carbon, which was derived from the oxidation of Fe(II) by nitric acid dominated the remarkably high efficiency with respect to the removal of phosphate. The activation energy for adsorption was calculated to be 10.53 and 18.88 kJ/mol for AC-Fe and AC/O-Fe, respectively. The results showed that the surface mass transfer and intra-particle diffusion were simultaneously occurring during the process and contribute to the adsorption mechanism.
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Affiliation(s)
- Zhengfang Wang
- Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China
| | - Mo Shi
- Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China
| | - Jihua Li
- Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China
| | - Zheng Zheng
- Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China.
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Shi M, Wang Z, Zheng Z. Effect of Na+ impregnated activated carbon on the adsorption of NH4(+)-N from aqueous solution. J Environ Sci (China) 2013; 25:1501-1510. [PMID: 24520687 DOI: 10.1016/s1001-0742(8)60227-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Two kinds of activated carbons modified by Na+ impregnation after pre-treatments involving oxidation by nitric acid or acidification by hydrochloric acid (denoted as AC/N-Na and AC/HCl-Na, respectively), were used as adsorbents to remove NH4(+)-N. The surface features of samples were investigated by BET, SEM, XRD and FT-IR. The adsorption experiments were conducted in equilibrium and kinetic conditions. Influencing factors such as initial solution pH and initial concentration were investigated. A possible mechanism was proposed. Results showed that optimal NH4(+)-N removal efficiency was achieved at a neutral pH condition for the modified ACs. The Langmuir isotherm adsorption equation provided a better fit than other models for the equilibrium study. The adsorption kinetics followed both the pseudo second-order kinetics model and intra-particle kinetic model. Chemical surface analysis indicated that Na+ ions form ionic bonds with available surface functional groups created by pre-treatment, especially oxidation by nitric acid, thus increasing the removal efficiency of the modified ACs for NH4(+)-N. Na(+)-impregnated ACs had a higher removal capability in removing NH4(+)-N than unmodified AC, possibly resulting from higher numbers of surface functional groups and better intra-particle diffusion. The good fit of Langmuir isotherm adsorption to the data indicated the presence of monolayer NH4(+)-N adsorption on the active homogenous sites within the adsorbents. The applicability of pseudo second-order and intra-particle kinetic models revealed the complex nature of the adsorption mechanism. The intra-particle diffusion model revealed that the adsorption process consisted not only of surface adsorption but also intra-particle diffusion.
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Affiliation(s)
- Mo Shi
- Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China.
| | - Zhengfang Wang
- Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China
| | - Zheng Zheng
- Environmental Science and Engineering Department, Fudan University, Shanghai 200433, China
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Chen TC, Shih YJ, Chang CC, Huang YH. Novel adsorbent of removal phosphate from TFT LCD wastewater. J Taiwan Inst Chem Eng 2013. [DOI: 10.1016/j.jtice.2012.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wang Z, Nie E, Li J, Yang M, Zhao Y, Luo X, Zheng Z. Equilibrium and kinetics of adsorption of phosphate onto iron-doped activated carbon. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2011; 19:2908-2917. [PMID: 22354356 DOI: 10.1007/s11356-012-0799-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 01/27/2012] [Indexed: 05/31/2023]
Abstract
PURPOSE Two series of activated carbons modified by Fe (II) and Fe (III) (denoted as AC/N-Fe(II) and AC/N-Fe(III)), respectively, were used as adsorbents for the removal of phosphate in aqueous solutions. METHOD The synthesized adsorbent materials were investigated by different experimental analysis means. The adsorption of phosphate on activated carbons has been studied in kinetic and equilibrium conditions taking into account the adsorbate concentration, temperature, and solution pH as major influential factors. RESULTS Maximum removals of phosphate are obtained in the pH range of 3.78-6.84 for both adsorbents. Langmuir isotherm adsorption equation well describes the experimental adsorption isotherms. Kinetic studies revealed that the adsorption process followed a pseudo-second order kinetic model. Results suggest that the main phase formed in AC/N-Fe(II) and AC/N-Fe(III) is goethite and akaganeite, respectively; the presence of iron oxides significantly affected the surface area and the pore structure of the activated carbon. CONCLUSIONS Studies revealed that iron-doped activated carbons were effective in removing phosphate. AC/N-Fe(II) has a higher phosphate removal capacity than AC/N-Fe(III), which could be attributed to its better intra-particle diffusion and higher binding energy. The activation energy for adsorption was calculated to be 22.23 and 10.89 kJ mol(-1) for AC/N-Fe(II) and AC/N-Fe(III), respectively. The adsorption process was complex; both surface adsorption and intra-particle diffusion were simultaneously occurring during the process and contribute to the adsorption mechanism.
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Affiliation(s)
- Zhengfang Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, People's Republic of China
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