Derivation of Optimum Study Factors for Samples Contaminated with Cd Using Electric/Magnetic Field and ORP

2013 ◽  
Vol 813 ◽  
pp. 519-524
Author(s):  
Sang An Ha ◽  
Jei Pil Wang
Keyword(s):  
Magnetic Field ◽  
Heavy Metals ◽  
Removal Rate ◽  
Underground Water ◽  
Liquid Electrode ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Of Heavy Metals ◽  
High Removal Rate ◽  
Membrane Treatment

A purpose of the present study is to derive optimum study factors for removal of heavy metals using combined alternating current electric/magnetic field and electric membranes for the area contaminated with heavy metals in soil or underground water. ORP (Oxidation Reduction Potential) analysis was conducted to determine an intensity of tendency for oxidation or reduction of the samples contaminated with heavy metals, and electrical membrane treatment was used with adjustment of concentrations and voltages of liquid electrode (Na2SO4) to derive a high removal rate. Removal constants were analyzed to be 0.0417, 0.119, 0.1594 when the voltages were 5V, 10V, 15V, respectively, and treatment efficiency was shown to increase as the liquid electrode concentration was increased. Keywords: heavy metals, electric/magnetic field, ORP, electrical membrane

Microbial Biomass and Enzyme Activities in Chromium and Lead-Contaminated Sediments

2013 ◽  
Vol 798-799 ◽  
pp. 1139-1143
Author(s):  
Chao Wang ◽  
Shuai Cheng ◽  
Pei Fang Wang ◽  
Yan Yan Ma
Keyword(s):  
Heavy Metals ◽  
Microbial Biomass ◽  
Enzyme Activities ◽  
Chemical Properties ◽  
Nitrogen And Phosphorus ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Organic Carbon Oxidation ◽  
The Relationship ◽  
Cr Contamination

The relationship between microbial biomass and enzyme activities under heavy metal pollution had attracted much attention in ecology. The experimental sediment samples were supplemented with Pb and Cr and incubated at room temperature for a month. Microbial properties such as microbial biomass, urease, catalase and cellulase activities, together with several chemical properties such as pH, total organic carbon , oxidation-reduction potential, total nitrogen and phosphorus were measured to evaluate changes in sediment qualities. Our results demonstrate that heavy metals would inhibit sediment microbe biomass and enzyme activities. Such decreases in sediments microbial biomass and enzyme activities by Pb and Cr contamination may help to evaluate heavy metals contaminated soil ecologies.

scholarly journals Biological Removal NOx from Simulated Flue gas in aerobic biofilter, by Jiang R., Huang S.B. and Yang J.

2013 ◽  
Vol 10 (2) ◽  
pp. 241-248
Keyword(s):  
Gas Phase ◽  
Flue Gas ◽  
Removal Rate ◽  
Nox Removal ◽  
Biological Removal ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
O2 Concentration ◽  
Blank Experiment ◽  
Nitrate And Nitrite

A bench-scale biofiltration system was developed to evaluate the NOx removal efficiency under high oxygen concentration. The system had been running for 120 days and kept on a steady NOx removal rate above 80%. A stable NOx removal with an efficiency of more than 80% from the gas phase can be obtained by the bioreactor concept, when flue gas containing NO (400-600 ppmv) and a certain O2 concentration (0-20%). In the blank experiment, less than 35% NO was removed as oxygen increased. The tendency of the three curves about NO removal rate with various O2 concentrations was mainly similar but some differences in the highest and lowest removal rate happened in the definite O2 concentration range. Oxygen was shown to have a significant effect on NOx removal at the first two or three days when oxygen concentration increased sharply. The higher concentration NO influent gas contained, the longer time the microflora need to regain activities. Compared with humidifier, microbial regenerator which was incorporated in biofilter can improve aerobic denitrifying bacteria activity by applying alternating oxic–anoxic conditions in the presence of nitrate and nitrite. Oxidation-Reduction Potential (ORP) and Dissolved Oxygen (DO) were used to control the dose of carbon source.

scholarly journals Removal of Heavy Metals Using Adsorption Processes Subject to an External Magnetic Field

Heavy Metals ◽  
2018 ◽  
Author(s):  
Ma. del Rosario Moreno Virgen ◽  
Omar Francisco González Vázquez ◽  
Virginia Hernández Montoya ◽  
Rigoberto Tovar Gómez
Keyword(s):  
Magnetic Field ◽  
Heavy Metals ◽  
External Magnetic Field ◽  
Removal Of Heavy Metals ◽  
Adsorption Processes

scholarly journals A Heavy Metal Network: Connecting Remediation Strategies

2018 ◽  
Vol 3 (1) ◽  
pp. 88
Author(s):  
Paola Posligua Chica ◽  
Carlos Banchón Bajaña ◽  
Elvito Villegas
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Reduction Potential ◽  
Human Life ◽  
Mining Industry ◽  
Anthropogenic Source ◽  
Chemical Parameters ◽  
Oxidation Reduction ◽  
Remediation Strategies ◽  
Oxidation Reduction Potential

Heavy metals in the environment are negatively affecting ecosystems and human life. The anthropogenic source of heavy metals has increased because of sludge from wastewater plants, tanneries, fertilizers, pesticides, and mining industry. As well as environmental conditions change, there is an effect of sedimentation of heavy metals in natural sediments which affect groundwater sources. Thus, the relevance of the present bibliometric work is to address the different interactions between heavy metals and natural sediments. Therefore, this work claims a perspective to predict heavy metal precipitation behaviors in the presence of cations and anions, changes of pH considering its mineral and organic forms, and, solid and liquid phase displacement, migrations towards the contaminated soil and cationic stabilization of heavy metals. In this sense, Cd, As, Mo, Cr, Al, Mn, Al, Cd, Hg, Zn, Pb, Cu, Co, and Ni are mostly correlated with basic pH and Ca/Mg/Fe/Mn minerals. This network has also found that there is a link connection between the contamination source i.e. fertilizers, pesticides and biosolids, and physical-chemical parameters like ionic strength, oxidation-reduction potential, and salinity. Thus, the scope of the present work includes a different perspective in looking remediation strategies by the generation of a connectionist system.Keywords: Speciation, bioaccumulation, adsorption, recalcitrance, network  

PLANTER BOX RAINGARDEN FOR ZINC REMOVAL FROM STORM WATER

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Mohammad Ramezanianpour ◽  
Alex Levien ◽  
George Ritchie
Keyword(s):  
Heavy Metals ◽  
Water Quality ◽  
Negative Impact ◽  
Removal Rate ◽  
Main Idea ◽  
Run Off ◽  
Vertical Hydraulic Conductivity ◽  
New Development ◽  
High Removal Rate ◽  
Methods Of Treatment

Urbanization creates problems for the natural water systems, such as an increase in run-off volume due to the impervious surfaces and a negative impact on groundwater recharge. These changes and exposure to contaminants such as suspended/dissolved solids and heavy metals severely degrade stormwater quality. In Christchurch, heavy metals such as zinc found in run-off, which is mainly sourced from galvanized roofing. The main idea of this research is to solve run-off issues at the source, along with the construction phase. This idea is aligned with the NZ's Unitary Plan to keep rainwater run-off after a new development equal or less than the run-off that occurred before the development. Different methods of treatment for roof run-off were evaluated in this research to propose a sustainable solution followed by an assessment. A multi-layered planter box raingarden was selected since it helps to landscape, improve water quality, and perform as an attenuation device. The research concentrated on maximizing water quality while maintaining a required flowrate. The planter box raingarden performed at a low vertical hydraulic conductivity rate of 164 mm/hr and achieved a high removal rate for heavy metals. The removal rate for dissolved zinc and total zinc was 99.7% and 99.1%, respectively. The results explained that the planter box raingarden performs well as an attenuation device while adsorb and filter contaminants remarkably.

Effect of pH on Pretreatment of Sulfate-Laden Wastewater for Mixotrophic Desulfurization-Denitrification Process

2010 ◽  
Vol 113-116 ◽  
pp. 429-433
Author(s):  
Wei Li ◽  
Xiao Liang ◽  
Jian Guo Lin
Keyword(s):  
Organic Carbon ◽  
Ph Value ◽  
Removal Rate ◽  
Subsequent Treatment ◽  
Sulfate Removal ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Sulfurous Compounds ◽  
Set Up ◽  
Denitrification Process

An anaerobic attached-growth bioreactor was set up to treat wastewater rich in sulfate and organic carbon. It was the pretreatment of mixotrophic desulfurization-denitrification process. With pH decreasing from 8 to 7, the sulfate removal rate and oxidation reduction potential increased, while sulfide generating rate and effluent pH decreased. When pH value was maintained at 7.5, the removal rates of sulfate and organic carbon reached 91.5% and 90.5%, respectively. Meantime, the generating rate of sulfide reached 47.8%, which was beneficial to the subsequent treatment and to the thorough removal of sulfurous compounds. The results showed that the suitable influent pH in sulfate reduction stage for the pretreatment of desulfurization-denitrification process was 7.5.

Modification of Sepiolite and its Ability to Remove Heavy Metals

2012 ◽  
Vol 508 ◽  
pp. 200-202
Author(s):  
Zhao Ping Chen ◽  
Ying Wang ◽  
Hang Yu Gu
Keyword(s):  
Heavy Metals ◽  
Removal Rate ◽  
Surface Structures ◽  
Modification Method ◽  
Removal Of Heavy Metals

The modification method and its eftect on the behavior of sepiolite, especially its ability to remove heavy metals, have be reaen systematically studied. Different pretreatment methods have led to various surface structures, which resulted in various effects on removal heavy metals. The processes of modification and removal of heavy metals have been optimized. The highest removal rate for Pb canch more than 96%.

scholarly journals The efficiency of a flocculent consisting of saw dust and bentonite clay in the removal of Fe and Ni from AMD

2020 ◽  
Vol 15 (1) ◽  
pp. 188-200
Author(s):  
I. O. Ntwampe ◽  
R. Mthembu
Keyword(s):  
Crystal Morphology ◽  
Mine Drainage ◽  
Bentonite Clay ◽  
High Sorption Capacity ◽  
Saw Dust ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Of Heavy Metals ◽  
High Sorption ◽  
Synthetic Acid

Abstract Sets of experiments were conducted by pouring 200 mL of synthetic acid mine drainage (AMD) into five 500 mL glass beakers, dosed with varying quantities of bentonite clay and saw dust interchangeably, mixed at 250 and 100 rpm for 2 and 10 mns respectively. The samples settled for 1 hour after which the pH, concentration, oxidation reduction potential (ORP) and percentage removal of heavy metals were measured. The results show that the removal efficiency of a flocculent on Ni and Fe is effective. The results show that saw dust does not affect the conductivity of a solution. The ORP of the samples with a flocculent with increasing bentonite clay exhibits a higher rate oxidation than that of a flocculent with increasing saw dust. The crystal morphology of the SEM micrographs with 1.5 g bentonite clay and 1.5 g saw dust show three types of structures, i.e. round flocs, elongated and clustered agglomerates which is indicative of high sorption capacity.

scholarly journals Efficiency of biochars in the removal of heavy metals

2019 ◽  
Vol 3 (3) ◽  
pp. 131 ◽  
Author(s):  
Denise Domingos dos santos Martins ◽  
Juan Carlos Valdés Serra ◽  
Joel Carlos Zukowski Junior ◽  
Marcelo Mendes Pedroza
Keyword(s):  
Heavy Metals ◽  
Effective Treatment ◽  
Membrane Separation ◽  
Chemical Precipitation ◽  
Production Costs ◽  
High Rate ◽  
Oxidation Reduction ◽  
Removal Of Heavy Metals ◽  
Exchange Membrane ◽  
Copper Lead

Toxic metals are naturally present in the environment even if there is no anthropic action. Several methods are used for the removal of these metals from water and effluents, such as: chemical precipitation, oxidation/reduction, filtration, ion exchange, membrane separation, and adsorption. Biosorption stands out as an effective treatment because it has a high rate of renewal in nature, low production costs, and high removal of metals due to the possibility of recovery of the contaminant, either by incinerating the biomass or by desorbing it. Thus, this study identified some biochars used as adsorbents for the removal of  copper, lead, chromium, and mercury in water. It can be concluded from this study that adsorption is a very efficient technique for removing or recovering heavy metals from the environment. These biocarbons are alternatives that can replace commercial activated carbon because, besides having a low production cost, they have been shown to efficiently remove metal ions, ensuring an effective treatment in compliance with effluent release standards.

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