Low-Cost Adsorbent in Treatment of Acid Mine Drainage in Cambodia: Chong Phlah, Mondulkiri
    1. Faculty of Geo-resources and Geotechnical Engineering, Institute of Technology of Cambodia, Russian Federation Blvd., P.O. Box 86, Phnom Penh, Cambodia

Received: April 15,2022 / Revised: Accepted: June 25,2022 / Published: June 30,2023

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Acidminedrainage(AMD)isamajorenvironmentaldistributedpollutantduetotheexposureofairandwaterfrom tailing and overburden produced from metals mining activity. AMD might degrade water to strong acidity, sulfide, iron (Fe), and other heavy metals contents due to the chemical consumption during the mineral extraction process. Thus, this study aimed to investigate the effectiveness of neutralization acid mine drainage caused by artisanal and small-scale mining at Chong Phlah, Mondulkiri, Cambodia. In this study, eggshell, limestone, and Calcium Carbonate (CaCO3) were applied as the adsorbent. The adsorbent was grounded to the size of less than 75μm, however, the eggshell was calcined at 900 oC for 2 hours before grinding. Limestone source was obtained from Battambong province, Cambodia. The experiment was conducted to study the influence of adsorbent dosage, varied time, adsorption kinetic, removal behavior, and stability of sample after treatment. Batch adsorption results showed that the maximum removal of As, Fe, and Mn was greater than 98%, 95%, and 83%, with eggshell, limestone, and CaCO3, respectively. The optimum contact time of As, Fe, and Mn removal was 480, 180, and 5 min, respectively. The pH between 5.8 and 6.6 was obtained after the adsorption process. In addition, As, Fe, and Mn following the pseudo-second-order kinetic model. The stability of arsenic and iron was arsenate and hematite, respectively. This demonstrated that the neutralization of acid mine drainage by the eggshell, limestone, and CaCO3 could be obtained. The application of this neutralization method using eggshell and limestone was considered cost-effective, readily available, and environmentally friendly to remove the heavy metals from acid mine drainage caused by tailing waste from artisanal and small-scale mining. The commercial CaCO3 in neutralization showed great effectiveness over eggshell and limestone, however, it is an expensive material.