| Title |
Phosphate removal from wastewater using scallop and whelk shells |
| ID_Doc |
25622 |
| Authors |
Brakemi, E; Michael, K; Tan, SP; Helen, H |
| Title |
Phosphate removal from wastewater using scallop and whelk shells |
| Year |
2023 |
| Published |
|
| DOI |
10.1016/j.jwpe.2023.104159 |
| Abstract |
Low-cost shells (scallop and whelk) were used as adsorbents for the removal of phosphate from synthetic and industrial wastewater. In synthetic wastewater samples, batch experimental conditions were optimised using a Central Composite Design (CCD). Column studies were carried out for the treatment of wastewater from a shellfish processing industry. The CCD results showed that scallop and whelk shells could adsorb phosphate over a broad pH value range (4.5-10.0) despite having a point of zero charge (pH(pzc)) of 9.4. However, maximum adsorption capacity was obtained at a pH value of 4.5, initial concentration of 90 mg/L PO43- and adsorbent dose of 10 g/L. The pseudo-second-order kinetic model fitted the batch experimental data for both scallop and whelk shells (R-2 >= 0.99) while the isotherm data was best fitted to Elovich (R-2 = 0.967) and Freundlich (R-2 = 0.9781) models respectively. The maximum adsorption capacity obtained experimentally for scallop and whelk shells was approximately 9.49 mg/g and 8.80 mg/g, respectively. Evidence of phosphate sorption onto the shells was shown via SEM-EDX, FTIR and XRD characterization studies. Scallop shells removed 46.68-85.48 % of phosphate from industrial wastewater in a fixed bed column without being exhausted after 7 h of operation. The desorption study results indicated the low regeneration potential of the spent adsorbents (<3.0 %), thus, suggesting a complex chemisorption mechanism. The results of this study indicate that unmodified waste shells are best employed in wastewaters having low phosphate levels and the spent adsorbents could be re-used as a slow-release fertilizer and as a conditioner in acidic soils. |
| Author Keywords |
Central composite design; Mollusc shells; Adsorption mechanism; Wastewater treatment; Circular economy |
| Index Keywords |
Index Keywords |
| Document Type |
Other |
| Open Access |
Open Access |
| Source |
Science Citation Index Expanded (SCI-EXPANDED) |
| EID |
WOS:001076581700001 |
| WoS Category |
Engineering, Environmental; Engineering, Chemical; Water Resources |
| Research Area |
Engineering; Water Resources |
| PDF |
https://doi.org/10.1016/j.jwpe.2023.104159
|