KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Choodum, AreeSubject: search.filters.subject.Phosphate recovery

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Magnetic calcium silicate hydrate–oyster shell waste nanocomposite for phosphate removal and recovery: RSM-based optimization, mechanism, and real water application
    (2025-09-01)
    Boonkanon, Chanita
    ;
    Wongniramaikul, Worawit
    ;
    Phawachalotorn, Chanadda
    ;
    Limwongsakorn, Somsak
    ;
    Choodum, Aree
    Magnetic nanocomposites offer an effective strategy for phosphate removal from wastewater, preventing eutrophication and enabling phosphate recovery for reuse as fertilizer—supporting a zero-waste approach. In this study, a novel hybrid nanocomposite composed of magnetized calcined oyster shell waste and calcium silicate hydrate (M-COS-CSH) was synthesized through a simple process completed within 5.2 h. Response Surface Methodology was employed for optimization: a Central Composite Design determined the optimal FeCl₃ and COS ratios, while a Box–Behnken Design optimized adsorption conditions including adsorbent dose (20–100 mg), initial phosphate concentration (10–90 mg L<sup>−1</sup>), contact time (15–75 min), and pH (3−11). Under optimal conditions (60 mg adsorbent, 10 mg L<sup>−1</sup> phosphate, 45 min, pH 6.28), M-COS-CSH achieved a predicted maximum removal efficiency of 97.30 %. An experimental removal efficiency of 98.06 % ± 0.19 % was obtained under the same conditions without pH adjustment (pH 6.84), offering a cost advantage. The adsorption process closely followed the Langmuir isotherm model (R<sup>2</sup> = 0.9963), with a maximum adsorption capacity of 161.29 mg g<sup>−1</sup>, and was best described by the pseudo-second-order kinetic model (R<sup>2</sup> = 1.0000). Characterization suggested a mechanism involving surface microprecipitation and inner-sphere complexation. Thermodynamic analysis confirmed the process to be endothermic and spontaneous (ΔG°: −9.97 to −10.84 kJ mol<sup>−1</sup>; ΔH°: 3.00 kJ mol<sup>−1</sup>; ΔS°: 43.52 J mol<sup>−1</sup> K<sup>−1</sup>). M-COS-CSH achieved phosphate removal ranging from 70.81 % ± 2.47 % to 94.24 % ± 0.39 % in real water samples. Even in the presence of competing anions at fivefold phosphate concentration, removal efficiency remained high (93.58 % ± 0.32 %), confirming the material's strong selectivity and suitability in complex matrices.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Effective recovery of phosphate from wastewater using biodegradable calcium-rich shell wastes composite macroporous cryogel
    (2024-06-20)
    Kaewnoo, Satabodee
    ;
    Wongniramaikul, Worawit
    ;
    Boonkanon, Chanita
    ;
    Taweekarn, Tarawee
    ;
    Kleangklao, Bussakorn
    The recovery of phosphorus from wastewater holds promise as a sustainable source of organic phosphorus for agricultural use while aiding in meeting legislative discharge limits for phosphorus to control and mitigate eutrophication. This study introduces a novel approach in which calcium-rich calcined oyster shell (Ca–COS) is immobilized on a starch-based monolithic cryogel, resulting in a green tablet (Cry–Ca–COS) capable of efficiently recovering phosphate from water through chemisorption on the material surface and precipitation in the liquid phase. The formed tablet prevents sorbent loss post-adsorption, facilitating reusability. Under optimal conditions (i.e., three 0.83 cm thick Cry–Ca–COS tablets, an initial phosphate concentration of 12 mg L<sup>−1</sup> in 1 L without pH adjustment (pH 6.3), and a contact time of 60 minutes), a phosphate removal efficiency of 83.11% ± 0.68% and a maximum removal capacity of 9.97 mg g<sup>−1</sup> were achieved. Both the Langmuir isotherm model and pseudo-second-order kinetic model exhibited good fits to the experimental data, with an estimated activation energy of 81.9 kJ mol<sup>−1</sup> and a positive enthalpy of 9.3 kJ mol<sup>−1</sup>, indicating an endothermic chemisorption process with a monolayer surface coverage of phosphate on Cry–Ca–COS. In real samples, Cry–Ca–COS demonstrated a high removal efficiency ranging from 98.48% ± 1.87%–99.16% ± 0.72%, with the adsorbed material biodegrading within 24 days under soil burial conditions. A preliminary study was conducted to explore the feasibility of utilizing phosphate-adsorbed Cry–Ca–COS as a fertilizer for cultivating water spinach (Ipomoea aquatica Forsk.), and further in-depth investigation is required for a comprehensive report in the future. Thus, Cry–Ca–COS emerges as an environmentally friendly and effective tool for phosphate removal and recovery.