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Synergistic role of PGPR and fungal isolates in mitigating As and Pb stress and promoting growth of Arachis hypogaea L.
(2026-01-01)
Sathya, C.
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Sridhar, D.
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Soytong, K.
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Song, J. J.
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Lalitha, S.
Heavy metals, also known as toxic metals, are major environmental pollutants that adversely impact all forms of life, disturbing soil ecology and reducing agricultural productivity. Certain indigenous microbes possess remarkable tolerance to these metals and play a vital role in restoring contaminated soils. In the present study, plant growth-promoting rhizobacteria and fungi were isolated from the rhizosphere and evaluated for their metal tolerance potential. Among the bacterial isolates (Pseudomonas alcaliphila PAS1, Pseudomonas aeruginosa PAS2, Pseudomonas toyotomiensis PTS3, Bacillus subtilis BSS1) expressing resistance to arsenic and lead which observed up to concentrations of 100–1200 ppm on nutrient agar. The fungal isolate Aspergillus japonicus (AJ01) exhibited tolerance up to 200 ppm of Pb and 500 ppm of As. Pot culture experiments were using Arachis hypogaea grown under As and Pb stresses with treatments of PGPR, PGPF, Compost and chemical control. Pseudomonas alcaliphila PAS1 was significantly enhanced plant growth by 100% and Pseudomonas aeruginosa PAS2 by 60% in contaminated soil, indicating strong tolerance and growth-promoting potential. Pseudomonas alcaliphila PAS1 increased chlorophyll content by 92.3% under As stress as compared to the control, while Pseudomonas toyotomiensis PTS3 showed a 70% increased, demonstrating high metal tolerance. In contrast, As and Pb stressed plants showed adverse effects. These findings highlighted the potential of selected PGPR and fungi as eco-friendly alternatives for the remediation and recovery of heavy metal-contaminated soils in Arachis hypogaea cultivation.
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Synergistic effect of arsenic removal from petroleum condensate via liquid-liquid extraction: Thermodynamics, kinetics, DFT and McCabe-Thiele method
(2023-12-01)
Purktimatanont, Kittamuk
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Mohdee, Vanee
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Pancharoen, Ura
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Maneeintr, Kreangkrai
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Punyain, Wikorn
This work presents the purification of petroleum condensate by removing arsenic ions via liquid-liquid extraction (LLE). Influence of pure and synergistic extractants is investigated. In terms of the practicability, following parameters are examined: the type of extractant, operating time, and temperature. Response surface methodology is used to design parameters such as organic-aqueous ratio and extractant concentration. Under optimal conditions; a mixture of 1 mol/L HCl and 0.02 mol/L thiourea with an organic/aqueous ratio of 1:4 at 323.15 K for 60 min, the extraction of arsenic reached 78.2 %. Further, batch simulation via two-stage counter-current extraction, and estimation by McCabe-Thiele diagram proved to be enhanced arsenic extraction to 95.3 %. Analysis by FTIR show that arsenic ions in petroleum condensate are formed as triphenylarsine compound ((C<inf>6</inf>H<inf>5</inf>)<inf>3</inf>As). The process of arsenic removal proved to be zero-order endothermic, irreversible and spontaneous reaction. The results obtained from the density functional theory (DFT) confirm that arsenic ions react with the synergistic extractant: effectively forming a covalent bond (As–S).
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Removal of As(III) from aqueous solution by the oyster shell powder–treated rice husk ash composite (OS-TRHA) pellet
(2019-07-04)
Khownpurk, Pichnipa
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Chandra-Ambhorn, Walairat
OS-TRHA pellets prepared from oyster shell (OS) powder and treated rice husk ash (TRHA) were used as the adsorbent for arsenite (As(III)) removal from contaminated water. The effect of the OS:TRHA ratio on As(III) removal performance was investigated via batch tests. The most appropriate ratio of OS and TRHA for OS-TRHA pellet preparation was 0.7:0.3 since it provided the acceptable As(III) adsorption capacity of about 26.2 mg g−1 without cracking. The OS-TRHA pellets before and after As(III) adsorption tests were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The mechanism of As(III) adsorption by OS-TRHA pellets was proposed. The experimental data correlated with the pseudo-second-order adsorption rate, and the adsorption behavior was better described by the Langmuir adsorption isotherm. The results of XRD, SEM, As(III) adsorption tests and calculation based on the Ca balance indicated that 25 wt% of OS-TRHA pellets was CaO that could react with As(III) and formed Ca-As-O (CaHAsO<inf>3</inf>) on the surface of the OS-TRHA pellets, while the other 75 wt% of OS-TRHA pellets was composed of CaSiO<inf>3</inf> and C-S-H compounds which bound the precursor powders into stable pellets without cracking.
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Arsenic removal from natural gas condensate using a pulsed sieve plate column and mass transfer efficiency
(2012-02-01)
Chaturabul, Srestha
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Wannachod, Pharannalak
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Rojanasiraprapa, Bongkotch
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Summakasipong, Supat
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Lothongkum, Anchaleeporn W.
This work applied a pulsed sieve plate column in conjunction with liquid-liquid extraction technique to remove arsenic from natural gas condensate. The relevant parameters, that is the type and concentration of the extractant, pulse velocity, volumetric-flow rate ratio of the condensate to the extractant, operating time, and extraction cycle were investigated. Mass transfer efficiency in terms of the overall height of transfer unit (HTU <inf>oy</inf>cm) and the interfacial area (m 2/m 3) were calculated. The highest percentage of arsenic removal in this study was 94% corresponding to the calculated HTU <inf>oy</inf> of 26 cm and the calculated interfacial area of 118 m 2/m 3 at the optimum conditions: the mixture of the extractant (1 M hydrochloric acid and 20% (v/v) methanol), pulse velocity of 20 mm/s, and volumetric-flow rate ratio of the condensate to the extractant of 1:4. By using continuous operation in the cycle mode, the percentages of arsenic removal were observed at 94, 85, and 80 from the respective 1st, 2nd, and 3rd cycles. The operation was based on the condition that fresh feed was introduced in each cycle while the extractant was reused. © Taylor and Francis Group, LLC.
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Simultaneous removal of arsenic and mercury from natural-gas-co-produced water from the Gulf of Thailand using synergistic extractant via HFSLM
(2011-03-01)
Lothongkum, Anchaleeporn Waritswat
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Suren, Sira
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Chaturabul, Srestha
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Thamphiphit, Nopphawat
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Pancharoen, Ura
The simultaneous separation of arsenic and mercury ions from natural-gas-co-produced water was well achieved by a synergistic extractant through a hollow fiber supported liquid membrane (HFSLM). Aliquat 336, Bromo-PADAP, Cyanex 923 and Cyanex 471 dissolved in toluene were used as the organic extractants or carriers. The transport system was studied on several variables: types of the extractants, concentration of the synergistic extractant, concentration of H<inf>2</inf>SO<inf>4</inf> (a co-extractant) in feed solution, types of stripping solutions (NaOH, DI water, HNO<inf>3</inf>, H<inf>2</inf>SO<inf>4</inf> and thiourea), and the number of separation cycles. The results indicated the superior performance of mercury removal to arsenic by every single extractant in this study. The synergistic effect on arsenic removal was observed by adding Cyanex 471 in Aliquat 336 resulting in the synergistic coefficient of 2.8. The regulate mercury discharge to the environment not higher than 5ppb was attained within 1-cycle separation by using the mixture of 0.22M Aliquat 336 and 0.06M Cyanex 471 as the synergistic extractant and 0.1M thiourea as the stripping solution with 0.2M H<inf>2</inf>SO<inf>4</inf> in feed solution. By 3-cycle separation, 94% arsenic extraction, which was below the legislation limit of 250ppb, was obtained. © 2010 Elsevier B.V.
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Treatment of arsenic ions from produced water through hollow fiber supported liquid membrane
(2009-08-12)
Pancharoen, Ura
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Poonkum, Woradej
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Lothongkum, Anchaleeporn Waritswat
Treatment of arsenic ions from produced water coming along with a gas separation plant in the Gulf of Thailand by hollow fiber supported liquid membrane (HFSLM) was studied. Cyanex® 923 (a mixture of phosphine oxide), tri-n-butylphosphate (TBP), bis(2, 4, 4-trimethylpentyl) dithiophosphinic acid (Cyanex® 301), tri-n-octylamine (TOA) and methyltrioctylammonium chloride (Aliquat 336) were used as the extractants. The stripping solution was sodium hydroxide. The concentration of the extractant in liquid membrane and concentration of sodium hydroxide were examined. In addition, the influence of various numbers of runs of the stripping solution through the HFSLM on the concentration of arsenic ions in the outlet stripping solution was observed. Of all the extractants used, 35% (v/v) Aliquat 336 attained high percentages of extraction and recovery of arsenic ions because it reacted with both undissociated arsenic (H<inf>3</inf>AsO<inf>3</inf>) and dissociated arsenics (H<inf>2</inf>AsO<inf>4</inf>- and HAsO<inf>4</inf>2-). Cyanex® 923, TBP and TOA had low extractability since Cyanex® 923 and TBP reacted only with undissociated forms while TOA reacted only with dissociated forms. In case of Cyanex® 301, although it offered a relatively high percentage of extraction but very poor recovery due to this extractant formed very strong complex species with arsenic ions, which slowed down and made the stripping difficult. It was found that the percentage of arsenic recovery increased with the concentration of sodium hydroxide and was almost constant after 0.5 M due to the limitation of mass transfer area of the hollow fibers. After 3-cycle separation, the extraction and recovery of arsenic ions from produced water were 91% and 72%, respectively. Accordingly, the concentration of arsenic ions of 0.1201 ppm in produced water was observed, which was in accordance with the legislation discharge of industrial effluent in Thailand. More arsenic ions were recovered by increasing the numbers of runs of the recycling stripping solution through the HFSLM. © 2009 Elsevier B.V. All rights reserved.
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Separation of As(III) and As(V) by hollow fiber supported liquid membrane based on the mass transfer theory
(2008-01-01)
Prapasawat, Tatchanok
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Ramakul, Prakorn
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Satayaprasert, Chairit
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Pancharoen, Ura
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Lothongkum, Anchaleeporn W.
Separation of As(III) and As(V) ions from sulphate media by hollow fiber supported liquid membrane has been examined. Cyanex 923 was diluted in toluene and used as an extractant. Water was used as a stripping solution. The extractability of As(V) was higher than As(III). When the concentration of sulphuric acid in feed solution and Cyanex 923 in liquid membrane increased, more arsenic ions were extracted into liquid membrane and recovered into the stripping solution. The mathematical model was focused on the extraction side of the liquid membrane system. The mass transfer coefficients of the aqueous phase (k <inf>i</inf> ) and organic phase (k <inf>m</inf> ) are 7.15×10 -3 and 3.45×10-2 cm/s for As(III), and 1.07×10-2 and 1.79×10-2 cm/s for As(V). Therefore, the rate-controlling step for As(III) and As(V) in liquid membrane process is the mass transfer in the aqueous film between the feed solution and liquid membrane. The calculated mass transfer coefficients agree with the experimental results. © 2008 Springer.
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Purely separation of mixture of mercury and arsenic via hollow fiber supported liquid membrane
(2007-09-01)
Sangtumrong, Seewalee
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Ramakul, Prakom
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Satayaprasert, Chairit
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Pancharoen, Ura
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Lothongkum, Anchaleeporn W.
The separation of mercury(II) and arsenic(III) ions from chloride media has been examined through a hollow fiber supported liquid membrane using tri-n-octylamine (TOA) as an extractant dissolved in toluene. The transport system was studied as a function of several variables: the concentration of the hydrochloric acid feed solutions, the concentration of TOA in the liquid membrane, the concentration of sodium hydroxide in the recovery solutions. According to the system, mercury(II) ions were extracted using TOA by rejecting arsenic (III) ions into raffinate because of the different forms of the mercury(II) and arsenic(III) ions in hydrochloric acid solutions. The maximum percentage of recovery for mercury(II) was 95 %; 100 % selectivity was obtained.

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