Treatment of compost as a source of organic material for bacterial consortium in the removal of sulfate and heavy metal lead (Pb) from acid mine drainage

Acid mine drainage can pollute the environment because it is acidic and contains toxic heavy metals. The purpose of this research was the application of a bacterial consortium to remove sulfate and reduce heavy metal lead (Pb) in acid mine drainage. The application was done in the bioreactor for acid mine drainage treatment that was treated with compost. Observations were made every five days and included observation of total bacterial growth using the Standard Plate Count (SPC) method, determination of sulfate content by gravimetry, determination of pH by use of pH meter, and determination of the concentration of heavy metal Pb using the AAS method. As a result, it was obtained that the treatment of non-sterile compost in acid mine drainage was able to reduce the initial heavy metal concentration of Pb of 84% and reduce the sulfate content by 72%, along with increasing pH and an increase in total bacterial growth. Meanwhile, sterile compost treatment was only able to reduce the Pb content by 63% and sulfate by 54%. This result indicates that the addition of compost is more effective than the treatment of sterile compost.

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Recent developments in materials used for the removal of metal ions from acid mine drainage

Applied Water Science ◽

10.1007/s13201-020-01350-9 ◽

2021 ◽

Vol 11 (2) ◽

Author(s):

Tebogo M. Mokgehle ◽

Nikita T. Tavengwa

Keyword(s):

Heavy Metal ◽

Surface Water ◽

Acid Mine Drainage ◽

Metal Ions ◽

Mine Drainage ◽

Acid Mine ◽

Adsorption Capacities ◽

Ion Imprinted ◽

Wide Range ◽

Ion Imprinted Polymers

AbstractAcid mine drainage is the reaction of surface water with sub-surface water located on sulfur bearing rocks, resulting in sulfuric acid. These highly acidic conditions result in leaching of non-biodegradeable heavy metals from rock which then accumulate in flora, posing a significant environmental hazard. Hence, reliable, cost effective remediation techniques are continuously sought after by researchers. A range of materials were examined as adsorbents in the extraction of heavy metal ions from acid mine drainage (AMD). However, these materials generally have moderate to poor adsorption capacities. To address this problem, researchers have recently turned to nano-sized materials to enhance the surface area of the adsorbent when in contact with the heavy metal solution. Lately, there have been developments in studying the surface chemistry of nano-engineered materials during adsorption, which involved alterations in the physical and chemical make-up of nanomaterials. The resultant surface engineered nanomaterials have been proven to show rapid adsorption rates and remarkable adsorption capacities for removal of a wide range of heavy metal contaminants in AMD compared to the unmodified nanomaterials. A brief overview of zeolites as adsorbents and the developent of nanosorbents to modernly applied magnetic sorbents and ion imprinted polymers will be discussed. This work provides researchers with thorough insight into the adsorption mechanism and performance of nanosorbents, and finds common ground between the past, present and future of these versatile materials.

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Influence of Monovalent Cations on the Efficiency of Ferrous Ion Oxidation, Total Iron Precipitation, and Adsorptive Removal of Cr(VI) and As(III) in Simulated Acid Mine Drainage with Inoculation of Acidithiobacillus ferrooxidans

Metals ◽

10.3390/met8080596 ◽

2018 ◽

Vol 8 (8) ◽

pp. 596 ◽

Cited By ~ 2

Author(s):

Yongwei Song ◽

Heru Wang ◽

Jun Yang ◽

Yanxiao Cao

Keyword(s):

Heavy Metal ◽

Acid Mine Drainage ◽

Acidithiobacillus Ferrooxidans ◽

Mine Drainage ◽

Metal Removal ◽

Heavy Metal Removal ◽

Monovalent Cations ◽

Iron Minerals ◽

Acid Mine ◽

Removal Efficiencies

Acid mine drainage is highly acidic and contains large quantities of Fe and heavy metal elements. Thus, it is important to promote the transformation of Fe into secondary iron minerals that exhibit strong heavy-metal removal abilities. Using simulated acid mine drainage, this work analyzes the influence of monovalent cations (K+, NH4+, and Na+) on the Fe2+ oxidation and total Fe deposition efficiencies, as well as the phases of secondary iron minerals in an Acidithiobacillus ferrooxidans system. It also compares the Cr(VI) (K2Cr2O7) and As(III) (As2O3) removal efficiencies of different schwertmannites. The results indicated that high concentrations of monovalent cations (NH4+ ≥ 320 mmol/L, and Na+ ≥ 1600 mmol/L) inhibited the biological oxidation of Fe2+. Moreover, the mineralizing abilities of the three cations differed (K+ > NH4+ > Na+), with cumulative Fe deposition efficiencies of 58.7%, 28.1%, and 18.6%, respectively [n(M) = 53.3 mmol/L, cultivation time = 96 h]. Additionally, at initial Cr(VI) and As(III) concentrations of 10 and 1 mg/L, respectively, the Cr(VI) and As(III) removal efficiencies exhibited by schwertmannites acquired by the three mineralization systems differed [n(Na) = 53.3 > n(NH4) = 53.3 > n(K) = 0.8 mmol/L]. Overall, the analytical results suggested that the removal efficiency of toxic elements was mainly influenced by the apparent structure, particle size, and specific surface area of schwertmannite.

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