Purpose Heavy metals are toxic pollutants released into the environment as a result of different industrial activities. Biosorption of heavy metals from aqueous solutions is a new technology for the treatment of industrial wastewater. The aim of the present research is to highlight the basic biosorption theory to heavy metal removal. Materials and methods Heterogeneous cultures mostly dried anaerobic bacteria, yeast (fungi), and protozoa were used as low-cost material to remove metallic cations Pb(II), Cr(III), and Cd(II) from synthetic wastewater. Competitive biosorption of these metals was studied. Results The main biosorption mechanisms were complexation and physical adsorption onto natural active functional groups. It is observed that biosorption of these metals was a surface process. The main functional groups involved in these processes were hydroxyl (–OH) and carboxylic groups (C=O) with 37, 52, and 31 and 21, 14, and 34 % removal of Pb(II), Cr(III), and Cd(II), respectively. Langmuir was the best model for a single system. While extended Langmuir was the best model for binary and ternary metal systems. The maximum uptake capacities were 54.92, 34.78, and 29.99 mg/g and pore diffusion coefficients were 7.23, 3.15, and 2.76 × 10−11 m2/s for Pb(II), Cr(III), and Cd(II), respectively. Optimum pH was found to be 4. Pseudo-second-order was the best model to predict the kinetic process. Biosorption process was exothermic and physical in nature. Conclusions Pb(II) offers the strongest component that is able to displace Cr(III) and Cd(II) from their sites, while Cd(II) ions are the weakest adsorbed component.
An innovative desalination method called electrosorption or capacitive deionization (CDI) has significant benefits for wastewater treatment. This process is performed by using a carbon fiber electrode as a working electrode to remove hexavalent chromium ions from an aqueous solution. The pH, NaCl concentration, and cell voltage were optimized using the Box-Behnken experimental design (BDD) in response surface methodology (RSM) to study the effects and interactions of selected variables. To attain the relationship between the process variables and chromium removal, the experimental data were subjected to an analysis of variance and fitted with a quadratic model. The optimum conditions to remove Cr(VI) ions were: pH of 2, a cell voltage of 4.
... Show MoreInfrastructure, especially wastewater projects, plays an important role in the life of residential communities. Due to the increasing population growth, there is also a significant increase in residential and commercial facilities. This research aims to develop two models for predicting the cost and time of wastewater projects according to independent variables affecting them. These variables have been determined through a questionnaire distributed to 20 projects under construction in Al-Kut City/ Wasit Governorate/Iraq. The researcher used artificial neural network technology to develop the models. The results showed that the coefficient of correlation R between actual and predicted values were 99.4% and 99 %, MAPE was
... Show MoreA new adsorbent was developed by integrating algae biomass (AG) into a chitosan (CN) matrix, followed by structural enhancement via crosslinking with pyromellitic dianhydride (PMDA) through a hydrothermal synthesis approach. This process resulted in the formation of a robust AG@CN-PMDA composite with improved physicochemical characteristics suitable for advanced adsorption applications. The AG@CN-PMDA composite was evaluated for its efficiency in removal of the cationic dye methyl violet 2B (MV 2B) from aqueous solution. The adsorption process was refined through the Box-Behnken design (RSM-BBD), evaluating three essential parameters: adsorbent dosage (A: 0.02–0.1 g/100 mL), pH (B: 4–10), and time (C: 5–20 min). The ideal conditions f
... Show MoreHydrate dissociation equilibrium conditions for carbon dioxide + methane with water, nitrogen + methane with water and carbon dioxide + nitrogen with water were measured using cryogenic sapphire cell. Measurements were performed in the temperature range of 275.75 K–293.95 K and for pressures ranging from 5 MPa to 25 MPa. The resulting data indicate that as the carbon dioxide concentration is increased in the gas mixture, the gas hydrate equilibrium temperature increases. In contrast, by increasing the nitrogen concentration in the gas mixtures containing methane or carbon dioxide decreased the gas hydrate equilibrium temperatures. Furthermore, the cage occupancies for the carbon dioxide + methane system were evaluated using the Van der Wa
... Show MoreIn Iraq, water shortages and drought, especially during the hot summer months, necessitates that municipal authorities adopt water reuse projects like reusing treated domestic wastewater for crop irrigation. This work gives the conceptual and basic design elements for the necessary steps of filtration, UV irradiation and chlorination to make such a wastewater fit for agricultural use. A typical rural community of 50,000 people is considered as an example case for which functionality and relative simplicity of the proposed designs are prime factors. The objectives are 1) to show what is required and 2) that the presented information may be utilized to embark on the following phases of detailed design and execution of such projects.
Two types of adsorbents were used to treat oily wastewater, activated carbon and zeolite. The removal efficiencies of these materials were compared to each other. The results showed that activated carbon performed some better properties in removal of oil. The experimental methods which were employed in this investigation included batch and column studies. The former was used to evaluate the rate and equilibrium of carbon and zeolie adsorption, while the latter was used to determine treatment efficiencies and performance characteristics. Expanded bed adsorber was constructed in the column studies. In this study, the adsorption behavior of vegetable oil (corn oil) onto activated carbon and zeolite was examined as a function of the concentr
... Show MoreIn this publication, several six coordinate Co(III)-complexes are reported. The reaction of 2,3-butanedione monoxime with ethylenediamine or o-phenylenediamine in mole ratios of 2:1 gave the tetradentate imine-oxime ligands diaminoethane-N,N`-bis(2-butylidine-3-onedioxime) H2L1 and o-phenylenediamine-N,N`-bis(2-butylidine-3-onedioxime), respectively. The reaction of H2L1 and H2L2 with Co(NO3)2, and the amino acid co-ligands (glycine or serine) resulted in the formation of the required complexes. Upon complex formation, the ligands behave as a neutral tetradantate species, while the amino acid co-ligand acts as a monobasic species. The mode of bonding and overall geometry of the complexes were determined through physico-chemical and spectro
... Show MoreThe azo dye brilliant reactive red K-2BP (λmax = 534 nm) is widely used for coloring textiles because of its low-cost and tolerance fastness properties. Wastewaters treatment that contains the dye by conventional ways is usually inadequate due to its resistance to biological and chemical degradation. During this study, the continuous reactor of an advanced oxidation method supported the use of H2O2/sunlight, H2O2/UV, H2O2/TiO2/sunlight, and H2O2/TiO2/UV for decolorization of brilliant reactive red dye from the effluent. The existence of an optimum pH, H2O2 concentration, TiO2 concentration, and d
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