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Author: search.filters.author.Chaiyaraksa, ChompoonutSubject: search.filters.subject.Magnetic biochar

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    Immobilization of cadmium in soil using magnetic biochar derived from Eichhornia crassipes
    (2020-08-01)
    Chaiyaraksa, Chompoonut
    ;
    Lokham, Nongnapa
    ;
    Kuikrong, Rawisara
    ;
    Artsanapaiboon, Sangarun
    Heavy metal contamination in an environment is a critical problem in Thailand that needs to be addressed urgently, particularly contaminated soil. This research aims to study the adsorption of cadmium ion by unmodified biochar and sodium dodecyl sulfate modified magnetic biochar (SDS-MB) derived from Eichhornia Crassipes. The adsorbent and soil characteristics were determined. Observed by scanning electron microscope (SEM), the surface of unmodified biochar (B) was smoother than SDS-MB. The X-ray diffractometer (XRD) pattern showed peaks for iron oxide. The values of point of zero charge (pH<inf>PZC</inf>) and acid neutralization capability (ANC) were 3 and 1000.3 meq/kg, respectively. The greatest adsorption of cadmium occurred when the pH of the wastewater was 8. The adsorption reached equilibrium within 1 h. It followed Freundlich, Temkin, and Dubinin-Radushkevich isotherm model and the pseudo-second-order kinetic. SDS-MB was mixed with sandy clay loam soil (pH 7.87) contaminated with cadmium 50 mg per kilogram soil at the ratio of 0-5%. The results from the extraction with ethylenediaminetetraacetic acid (EDTA), ammonium acetate, calcium chloride, diethylene triamine pentaacetic acid (DTPA), and sequential extraction method indicated that 5% mixing ratio showed the best ability to reduce cadmium movement in the soil. Cadmium in a form that bound to oxide and a form that bound to organic matter significantly increased.
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    Adsorption of copper (II) and nickel (II) by chemical modified magnetic biochar derived from eichhornia crassipes
    (2019-05-01)
    Chaiyaraksa, Chompoonut
    ;
    Boonyakiat, Watcharapol
    ;
    Bukkontod, Wannisa
    ;
    Ngakom, Wanvisa
    A heavy metal contamination problem in Thailand is an important issue that needs to be addressed urgently, particularly contaminated in water. Heavy metal contamination in water can spread to other environments faster. This research aims to apply chitosan-magnetic biochar synthesized from water hyacinth in order to solve the problem of copper and nickel contaminated in water. Data from SEM indicated that chitosan-magnetic biochar had a smoother surface and had smaller holes than the magnetic biochar. When tested with Autosorb-1, results indicated that the adsorbent with chitosan had a slightly lower porosity compared to without chitosan. Data from FTIR found evidence of chitosan on the adsorbent. According to the XRD study, peaks of iron oxide presented. The point of zero charges (pH<inf>PZC</inf>) of chitosan-magnetic biochar was 7.03. The adsorption isotherms, kinetics, and thermodynamics were observed. The adsorption of both Cu and Ni followed Langmuir isotherm. The value of q<inf>max</inf> for Cu was 38.4615 mg/g and for Ni was 0.4858 mg/g. The R<sup>2</sup> value of Dubinin-Radushkevich isotherm was also high. The E value of Cu and Ni was 0.316 kJ/mol and 1.8962 kJ/mol, respectively. The best-fitting kinetic model for Cu was the pseudo-second-order model and for Ni was the intra-particle diffusion. The adsorption was an endothermic process. The process was spontaneous at high temperatures and non-spontaneous at low temperatures.