Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent. It has been demonstrated that when equimolar quantities of the metals ...
Contamination caused by heavy metals in wastewater has a high potential of risk because they easily penetrate in to the trofic chain accumulating as organometallic compounds. In this work, the expression of mice metallothionein in E. coli (pMt-Thio) was examined as a strategy to enhance metal biosorption efficiency of bacterial biosorbents for Pb(II) and Cd(II) ions. The results showed that ...
Lead (Pb2+) is a heavy metal which is utilized in several industries and can have severe impact on the environment and human health. Research work has been carried out lately on the feasibility of using various low cost materials in the removal of heavy metals from wastewater. In this study, the feasibility of utilizing raw rice straw for removal of Pb2+ from water through biosorption was ...
The purpose of this research was to analyze the adsorption behavior of Fe(II) and Fe(III) ions in aqueous solution onto beads of naturally derived chitosan cross-linked with tripolyphosphate in a batch system. Effects of solution pH, contact time and amount of adsorbent were regarded in the kinetic and equilibrium studies. The optimum conditions of adsorption for Fe(II) and Fe(III) were ...
In the present study, the treatment of metal plating wastewater containing complexed metals originating from the nickel and zinc plating process by electrocoagulation (EC) using stainless steel electrodes was explored. In order to improve the organic matter removal efficiency, the effect of H2O2 addition to the electrocoagulation (the combined EC/Fenton process) application was investigated. For ...
A heavy metal binding bacterium Pseudomonas putida 5-x was used as biosorbent for heavy metal removal from wastewater. In order to compete with physical adsorbent, the optimisation of the cell preparation technique for further improving its biosorption capacity was conducted. Results showed that the compositions of medium for cell culturing, cell growth age and cell pre-treating technique would ...
Phytotechnologies involving use of plants for pollutant removal gained importance during the last two decades. Terrestrial and aquatic plants possess high metal sorption capacity, and hence find their use as inexpensive materials for removing metals from environment. Aquatic biomass irrespective living or dead, exhibits capacity to remove heavy metals from wastewater. The sequestration of heavy ...
The effect of effluent composition on the efficiency of hydroxide precipitation of Cd(II), using both lime and magnesia as precipitants, has been modelled by the solubility domain approach in order to provide wastewater effluent treatment limits, and has been experimentally validated. Common anionic species such as Cl−,, SO42−, and CO32−, have been treated. Solubility domain ...
Optimizing Wastewater Metals Removal Making Wastewater Metals Insoluble for Easy Removal To remove metals from wastewater, the metals need to be insoluble (not in solution). Many facilities, such as in the plating operations, use chelating agents to keep the metals in solution thus insuring a uniform and continuous layer of plated metal. Other chelating agents come in the form of ammonia and ...
The ability of some Mediterranean plant species to absorb heavy metals present in wastewater from treatment plants is researched. Their tolerance to high concentrations of heavy metals is also assessed. Myoporum sp., Nerium oleander and Geranium sp. were irrigated with wastewater, normal irrigation water, and irrigation water enriched with metals. The concentration of metals in the wastewater, ...
This paper describes a comparative evaluation of collectors for metal removal by precipitation/flotation in samples of wastewaters from an electroplating industry. Precipitation/flotation was found to be successful over a great range of pH (3-12). The toxic metal ions lead (II), nickel (II), tin (II), iron (II) and aluminium (III) were stripped from contaminated industrial samples to ...
We have previously patented a process for the extraction of toxic and valuable metals from foundry sands using a thermostatted column. In this paper, we describe a similar device for the removal of toxic metals from wastewater sludge. The wastes were finely ground and suspended in an aqueous pulp, and 10-40g of mineral acid or sodium hydroxide were added to reach a pH of 2, 5, 7 and 10, together ...
There is a need to develop innovative and alternative technologies that can remove toxic heavy metal pollutants from wastewater. In this study, two agricultural residues, cotton stalks and apricot seeds, were used to adsorb copper and lead in solutions. Sorption capacities of agricultural wastes were significantly affected by solution pH, adsorbent mass and adsorbent particle size. The adsorption ...
After checking the success of the biosorption process to remove heavy metals from wastewater using olive tree pruning as a cheap biosorbent in the laboratory scale, the scale-up is necessary to progress towards industrial applications chance. The aim of this work was the study of the effect of scale-up in the process of biosorption of Pb(II) with olive tree pruning in a packed bed column. ...
The applicability of an electrochemical Fenton-type process (EF-HOCl-ReFe) to the treatment of three actual wastewaters, namely wastewater from an automobile factory (automobile wastewater), metal scrap-cleansing wastewater, and municipal wastewater, is discussed in this research. The EF-HOCl-ReFe successfully removed the chemical oxygen demand (COD) from automobile wastewater pre-treated by ...
Heavy metal pollution is a serious environmental concern worldwide, resulting in both environmental and human harm. Recently, studies have shown that environmental biotechnologies based on sulfate reduction offer a potential for removal of toxic heavy metals. Biological iron sulfide composites are iron sulfide compounds generated in situ by sulfate-reducing bacteria. In this study, microscopic ...
There is much debate in academia, as to what elements should be considered “heavy metals”. Some criteria depend on density, some on atomic number, and some on chemical behavior. In the water treatment industry, we tend to concern ourselves with the more common and more toxic variety. Such heavy metals may include mercury, cadmium, lead, chromium, and copper. Arsenic is also ...
An in situ sorption was conducted to assess the behaviour of cations in a mining wastewater reservoir. Sorption experiments on test materials showed that biomass mainly bound uranium, copper, lead, zinc, and nickel, whereas goethite bound arsenic and chromium. Clay minerals bound both barium and rare earth elements. The lacustrine sediments mainly contained iron oxy-hydroxides. Desorption ...
Affinity separation is becoming well established for the purification and recovery of metals from industrial wastewaters. Although the method has been successfully applied on a bench-scale, there is a need for reaction engineering studies to scale-up the process for use in large-scale wastewater purification and recovery of valuable metals. In this study, a pilot-scale packed-bed reactor has been ...
The recycling of copper and nickel from metallurgical wastewater using emulsion liquid membrane (ELM) was studied. P507 (2-ethylhexyl phosphonic acid-2-ethylhexyl ester) and TBP (tributyl phosphate) were used as carriers for the extraction of copper and nickel by ELMs, respectively. The influence of four emulsion composition variables, namely, the internal phase volume fraction (ϕ), ...