scholarly journals Comparison of heavy metal removal efficiencies in four activated sludge processes

2015 ◽  
Vol 22 (10) ◽  
pp. 3788-3794 ◽  
Author(s):  
Jun Yang ◽  
Ding Gao ◽  
Tong-bin Chen ◽  
Mei Lei ◽  
Guo-di Zheng ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Activated Sludge ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Removal Efficiencies ◽  
Activated Sludge Processes

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.

Heavy metal-binding proteins from metal-stimulated bacteria as a novel adsorbent for metal removal technology

2006 ◽  
Vol 53 (6) ◽  
pp. 221-226 ◽  
Author(s):  
D. Sano ◽  
K. Myojo ◽  
T. Omura
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Activated Sludge ◽  
Metal Binding ◽  
Binding Proteins ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Copper Ion ◽  
Amino Acid Sequences ◽  
Heavy Metal Binding

Water pollution with toxic heavy metals is of growing concern because heavy metals could bring about serious problems for not only ecosystems in the water environment but also human health. Some metal removal technologies have been in practical use, but much energy and troublesome treatments for chemical wastes are required to operate these conventional technologies. In this study, heavy metal-binding proteins (HMBPs) were obtained from metal-stimulated activated sludge culture with affinity chromatography using copper ion as a ligand. Two-dimensional electrophoresis revealed that a number of proteins in activated sludge culture were recovered as HMBPs for copper ion. N-termini of five HMBPs were determined, and two of them were found to be newly discovered proteins for which no amino acid sequences in protein databases were retrieved at more than 80% identities. Metal-coordinating amino acids occupied 38% of residues in one of the N-terminal sequences of the newly discovered HMBPs. Since these HMBPs were expected to be stable under conditions of water and wastewater treatments, it would be possible to utilize HMBPs as novel adsorbents for heavy metal removal if mass volume of HMBPs can be obtained with protein cloning techniques.

Stimulation of activated sludge cultures for enhanced heavy metal removal

1995 ◽  
Vol 67 (5) ◽  
pp. 822-827 ◽  
Author(s):  
Duk Chang ◽  
Kensuke Fukushi ◽  
Sambhunath Ghosh
Keyword(s):  
Heavy Metal ◽  
Activated Sludge ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Stimulation Of

scholarly journals Efficient removal of heavy metals from melting effluent using multifunctional hydrogel adsorbents

2018 ◽  
Vol 78 (4) ◽  
pp. 982-990 ◽  
Author(s):  
Jianhong Ma ◽  
Yuanmeng Zhang ◽  
Yanhong Tang ◽  
Yuanfeng Wei ◽  
Yutang Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Mechanical Strength ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
High Water ◽  
Poly Vinyl Alcohol ◽  
Removal Of Heavy Metals ◽  
Cross Linkage ◽  
Removal Efficiencies

Abstract It is hard to balance high water permeability and good mechanical strength of hydrogel adsorbents. In this study, an enhanced double network hydrogel adsorbent of poly (vinyl alcohol)/poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PVA/PAMPS) was prepared via simple free-radical polymerization. Hydrophilic PAMPS guaranteed high swellability of the adsorbent, which made the sufficient diffusion of metal ions towards adsorbent inside. Meanwhile, the cross-linkage between PVA and PAMPS chains ensured good mechanical strength of the adsorbent. Significantly, the introduction of multifunctional groups (-NHR, -SO3H and -OH) endowed the adsorbent with both chelation and ion exchange function for enhancing heavy metal adsorption. The maximum adsorption capacities of Pb2+ and Cd2+ reached 340 and 155.1 mg/g, respectively. The adsorbent could efficiently remove heavy metals in melting effluent, especially Pb2+ and Cd2+. The removal efficiencies reached 88.1% for Pb2+, 91.4% for Cd2+, 70.4% for Zn2+, 77.4% for Cu2+, 42.5% for Mn2+, 45.1% for Ni2+ and 95.4% for Fe3+ using 2 g/L adsorbent in 2 h. Moreover, the adsorbent showed a good reusability, and the removal efficiencies maintained 94% for Pb2+ and 93% for Cd2+ in the fifth cycle (m/V = 1 g dry gel/L). This work developed a highly practical hydrogel adsorbent for heavy metal removal from wastewater.

Mechanisms of heavy-metal removal by activated sludge

Chemosphere ◽  
2009 ◽  
Vol 75 (8) ◽  
pp. 1028-1034 ◽  
Author(s):  
F. Pagnanelli ◽  
S. Mainelli ◽  
L. Bornoroni ◽  
D. Dionisi ◽  
L. Toro
Keyword(s):  
Heavy Metal ◽  
Activated Sludge ◽  
Metal Removal ◽  
Heavy Metal Removal

scholarly journals Removal of Heavy Metals from Wastewater Using Novel Polydopamine-Modified CNTs-Based Composite Membranes

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2120
Author(s):  
Faizah Altaf ◽  
Shakeel Ahmed ◽  
Muhammad Usman ◽  
Tahira Batool ◽  
Jaweria Shamshad ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Composite Membranes ◽  
Low Concentrations ◽  
Removal Of Heavy Metals ◽  
Removal Efficiencies ◽  
Immense Potential ◽  
Maximum Removal

The presence of major heavy metals including Pb2+, Cu2+, Co2+, Ni2+, Hg2+, Cr6+, Cd2+, and Zn2+ in water is of great concern because they cannot degrade or be destroyed. They are toxic even at very low concentrations. Therefore, it is necessary to remove such toxicants from water. In the current study, polydopamine carbon nanotubes (PD-CNTs) and polysulfone (PS) composite membranes were prepared. The structural and morphological features of the prepared PDCN composite membranes were studied using FTIR, XRD, SEM, and EDS. The potential application of PDCNs for heavy metal removal was studied for the removal of Pb2+, Cr6+, and Cd2+ from wastewater. The maximum removal efficiency of 96.1% was obtained for Cr6+ at 2.6 pH using a composite membrane containing 1.0% PD-CNTs. The removal efficiencies decreased by 64.1 and 73.4, respectively, by enhancing the pressure from 0.50 up to 0.85 MPa. Under the same circumstances, the percentages of Pb+2 removal at 0.49 bar by the PDCNS membranes containing 0.5% and 1.0% PD-CNT were 70 and 90.3, respectively, and decreased to 54.3 and 57.0, respectively, upon increasing the pressure to 0.85 MPa. The results showed that PDCNS membranes have immense potential for the removal of heavy metals from water.

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