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Author: search.filters.author.Khownpurk, Pichnipa

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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
    ;
    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<sup>−1</sup> 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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    Preparation and characterization of oyster shell powder-treated rice husk ash adsorbent pellet for As(III) removal
    (2018-08-14)
    Khownpurk, Pichnipa
    ;
    Chandra-Ambhorn, Walairat
    The adsorbent pellet for As(III) removal was prepared from ground oyster shell and rice husk ash. The effects of particle size of oyster shell powder (OS) and the ratio between the OS and Treated rice husk ash (TRHA) on the stability of the adsorbent pellet were studied. The adsorbent pellet was characterized by XRD, XRF and SEM. The solubility and As(III) adsorption tests were performed. The results showed that the adsorbent pellet prepared from OS size <106 μm with OS:TRHA ratio of 0.7:0.3 could provide As(III) maximum adsorption capacity of approximately 26.20 mg/g. Furthermore, the XRD and SEM results indicated that the adsorbent pellet could consist of two parts i.e. CaO that could adsorb As(III) in the form of Ca-As-O and the CaSiO<inf>3</inf> and C-S-H compounds which behaved as a binder to bind the precursor powders to be stable adsorbent pellet without cracking.
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    Arsenic adsorption using the adsorbent synthesised from oyster shell
    (2017-01-01)
    Khownpurk, Pichnipa
    ;
    Wongpromrat, Wichitra
    ;
    Chandra-Ambhorn, Walairat
    Ground oyster shells were calcined and used as an adsorbent to remove As (III) from contaminated water. Adsorption experiment was performed by batch tests. The effect of pH on the adsorption performance was investigated. The result showed that at the initial concentration of 100 mg/L, over the pH range of 5-11, the highest efficiency was obtained at pH 11. The experimental data better correlated with pseudo-second order model. The maximum adsorption capacity (q<inf>m</inf>) of approximately 195.5 mg/g was obtained at pH 11.