The Efficacy of Ca-Mg-(OH)2 Nanocomposite on the Removal of Manganese from Mine Effluent Contaminated River Water

EasyChair Preprint 8131

Abstract

The ever-growing contamination of surface water by effluent emanating from mining activities has been an issue of prime concern to national and international scientific communities. Of paramount concern is the introduction of manganese to different receiving environmental compartments such as surface waterbodies. Manganese has the potential to impart colour to waterbodies, gives water a metallic taste, and it has been (eco)-toxicologically determined to cause hallucinations, forgetfulness and nerve damage. As such, this has deemed the need to manage and remove these contaminants, especially in drinking water. Herein, effective removal of manganese from mine effluent contaminated river water using CaMg(OH)₂ nanocomposite was reported. The nanocomposite was prepared by utilizing mechanochemical synthesis method, at 1:1wt% mass ratio of MgO and CaO to fabricate Ca-Mg-(OH)₂ nanocomposite. Batch experimental procedures were used to achieve the objectives of this study, specifically contact time (min), feedstock dosage (g), and mixing speed (rpm). Results revealed that 30 minutes of mixing time, 0.5 g of dosage in 500 mL of an aqueous solution, and 250 rpm of mixing speed were the optimum conditions for the removal of manganese. Thenceforth, the nanocomposite showed that at the optimum conditions, the manganese removal efficiency was achieved at 87% and pH increased from 7.55 to 7.81 while turbidity was reduced from 8.21 to 1.17 NTU. The nanocomposite demonstrated superior performance as compared to individual materials. PHREEQC geochemical model confirmed that manganese existed as Mn²⁺ and it was removed as manganite, rhodochrosite, and pyrochrosite. As such, findings from this confirmed the performance of Ca-Mg-(OH)₂ nanocomposite in the treatment of surface water contaminated by manganese from catchment mining activities.

Keyphrases: Contaminated river water, Manganese removal, model

@booklet{EasyChair:8131,
  author    = {Kgolofelo Nkele and Lizzy Mpenyana-Monyatsi and Vhahangwele Masindi},
  title     = {The Efficacy of Ca-Mg-(OH)2 Nanocomposite on the Removal of Manganese from Mine Effluent Contaminated River Water},
  howpublished = {EasyChair Preprint 8131},
  year      = {EasyChair, 2022}}