scholarly journals Sequential Abatement of FeII and CrVI Water Pollution by Use of Walnut Shell-Based Adsorbents

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 218
Author(s):  
Marius Gheju ◽  
Ionel Balcu
Keyword(s):  
Water Treatment ◽  
Mine Drainage ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Walnut Shell ◽  
Batch Experiments ◽  
Treatment Processes ◽  
Experimental Parameters ◽  
Shell Powder ◽  
Synthetic Acid

In this study walnut shells, an inexpensive and readily available waste, were used as carbonaceous precursor for preparation of an innovative adsorbent (walnut-shell powder (WSP)) which was successfully tested for the removal of FeII from synthetic acid mine drainage (AMD). Then, the exhausted iron-contaminated adsorbent (WSP-FeII) was recovered and treated with sodium borohydride for the reduction of adsorbed FeII to Fe0. The resulting material (WSP-Fe0) was subsequently tested for the removal of CrVI from aqueous solutions. Treatability batch experiments were employed for both FeII and CrVI-contaminated solutions, and the influence of some important experimental parameters was studied. In addition, the experimental data was interpreted by applying three kinetic models and the mechanism of heavy metal removal was discussed. The overall data presented in this study indicated that fresh WSP and WSP-Fe0 can be considered as promising materials for the removal of FeII and CrVI, respectively. Furthermore, the present work clearly showed that water treatment residuals may be converted in upgraded materials, which can be successfully applied in subsequent water treatment processes. This is an example of sustainable and environmentally-friendly solution that may reduce the adverse effects associated with wastes and delay expensive disposal methods such as landfilling or incineration.

Polyvinyl alcohol/polysaccharide hydrogel graft materials for arsenic and heavy metal removal

2015 ◽  
Vol 39 (7) ◽  
pp. 5823-5832 ◽  
Author(s):  
Md. Najmul Kabir Chowdhury ◽  
Ahmad Fauzi Ismail ◽  
Mohammad Dalour Hossen Beg ◽  
Gurumurthy Hegde ◽  
Rasool Jamshidi Gohari
Keyword(s):  
Heavy Metal ◽  
Water Treatment ◽  
Polyvinyl Alcohol ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Hydrogel Formation ◽  
Polysaccharide Hydrogel ◽  
Metallic Species

Polyvinyl alcohol/polysaccharide hydrogel formation ((A)–(C)) and metallic species adsorption ((D)) for water treatment.

scholarly journals 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 ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 596 ◽  
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.

Removal of Pb(II) by adsorption onto Chinese walnut shell activated carbon

2015 ◽  
Vol 72 (6) ◽  
pp. 983-989 ◽  
Author(s):  
Zheng-ji Yi ◽  
Jun Yao ◽  
Yun-fei Kuang ◽  
Hui-lun Chen ◽  
Fei Wang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Walnut Shell ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Chinese Walnut ◽  
Maximum Removal

The excessive discharge of Pb(II) into the environment has increasingly aroused great concern. Adsorption is considered as the most effective method for heavy metal removal. Chinese walnut shell activated carbon (CWSAC) was used as an adsorbent for the removal of Pb(II) from aqueous solution. Batch experiments were conducted by varying contact time, temperature, pH, adsorbent dose and initial Pb(II) concentration. Adsorption equilibrium was established within 150 min. Although temperature effect was insignificant, the Pb(II) adsorption was strongly pH dependent and the maximum removal was observed at pH 5.5. The Pb(II) removal efficiency increased with increasing CWSAC dosage up to 2.0 g/L and reached a maximum of 94.12%. Langmuir and Freundlich adsorption isotherms were employed to fit the adsorption data. The results suggested that the equilibrium data could be well described by the Langmuir isotherm model, with a maximum adsorption capacity of 81.96 mg/g. Adsorption kinetics data were fitted by pseudo-first- and pseudo-second-order models. The result indicated that the pseudo-first-order model best describes the adsorption kinetic data. In summary, CWSAC could be a promising material for the removal of Pb(II) from wastewater.

Removal of heavy metals using a wetland batch system with Carrizo (Phragmites Australis)

2020 ◽  
Author(s):  
Maribel Guzman ◽  
Maggy Romero ◽  
Michael Flores ◽  
Sebastian Bravo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Phragmites Australis ◽  
Mine Drainage ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Ammonia Nitrogen ◽  
Abandoned Mines ◽  
Slight Variation ◽  
Removal Of Heavy Metals

Abstract One of the greatest environmental issues related to the development of the mining activity is the generation of Acid Mine Drainage (AMD). This effluent generated by active and abandoned mines in Peru produces multiple discussions about the role of the industry for a sustainable development. Many methods have been developed for AMD treatment, being wetlands a good option for heavy metal removal. In this sense, removal of heavy metal by using laboratory constructed wetlands with Phragmites Australis was studied. During a 9-day period the variation of different physicochemical parameters and heavy metals concentrations was recorded. The pH decreased to a constant value of 8.24 after the sixth day. The electrical conductivity presented a slight variation from 1 to 1.33 µS cm-1 on the ninth day. Moreover, fluctuating values of Dissolved Oxygen and Turbidity were observed. A reduction between 69% and 93% of ammonia nitrogen (NH3-N) was registered. Cu concentration was reduced in 68% and 87%; Zn concentrations dropped in 53% and 95%; and Pb was reduced in 20% and 55%. It was concluded that Phragmites Australis can be an alternative in the treatment of the contaminants produced by AMD.

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