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This study deals with removing crude oil droplets from colloidal oil in water emulsions. The target was the development of efficient adsorbents for the tertiary treatment of industrial-produced water (PW). The novel adsorbent was designed from recycled low-density polyethylene (LDPE) powder grafted by the cationic polymer. The cationic polymer was synthesized directly on the LDPE surface by plasma-induced radical polymerization. A positively charged adsorbent was chosen due to the negative character of oily droplets to enhance separation efficiency in treating oil-water emulsions. The separation was performed in both batch and filtration modes. Absorption/adsorption uptake capacities showed a sigmoidal S-shape that was analyzed using the Sips model and compared with the newly developed empirical model. Both models showed a remarkable coincidence in the description of experimental data. The separation efficiency of the novel adsorbent was also tested in a filtration mode mimicking a commonly used deep-bed filtration technology. The comparison of the separation efficiency for various sorbents indicated a supreme performance of novel adsorbent. This study demonstrates the potential of a relatively cheap, prepared commodity-based adsorbent for the purification of emulsified oily polluted water in both batch and filtration configurations. This study also contributes to the recycling of polyethylene waste because LDPE attracts meager interest in recycled LLDPE due to many obstacles to reusing LDPE waste for its reprocessing as packaging materials. [ABSTRACT FROM AUTHOR]

A new hybrid method of utilizing Evidential Reasoning (ER) approach and Geographic Information System (GIS) was applied to find the optimum location of a Combined Heat and Power (CHP) incineration plant in Guilan province. According to guidelines and prevailing conditions, thirteen criteria were analyzed and divided to three main sections of environmental, social and economic categories. Most of the data in the study were obtained from local organizations and satellite images. To weight the criteria, evidential reasoning was applied to aggregate the decision-makers' opinions, and to find the potential sites; spatial analysis was done through the GIS. The result of suitability analysis indicates that about 0.07 % of total area of Guilan province is "the most suitable" region for the incineration plant and 0.05 %, 0.07 %, 2.77%, and 97.04 % are in the class of "suitable", "relatively suitable", "least suitable" and "limited". The areas with an area of larger than 40,000 m2 which is the necessary area for a 9 MW incineration plant were classified as alternatives for incineration CHP plant locations (A 1 -A 7). All the locations were investigated to be near rural areas, which might bring inevitable harm to the adjacent communities. Also, the low amount of "most suitable region" and "suitable region" foster a sense of concerns, which should be addressed by applying a sustainable approach for preserving the environment. The techno-economic analysis presented in this study indicates that the project is not economically beneficial at all. [ABSTRACT FROM AUTHOR]

Humic substances (HSs) are a group of complex macromolecular polymeric compounds originating from the decomposition of plant residuals and other organic matter. Within the presence of micro-pollutants and heavy metals, HSs negatively act upon potable water quality by contributing to aesthetic problems such as yellowish or brownish color and annoying taste and odor. They are also responsible for re-growth of pathogenic microorganisms and fouling of membranes in water distribution systems. More importantly, these high-molecular-weight polymers have been noted to be the major contributor to the formation of disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). Considering these harmful effects, removal of HSs is one of the significant tasks in drinking water treatment. For this purpose, this study aimed to explore the effects of various operating parameters (initial concentration, initial pH, electrical conductivity, pulse time, pulse number, and process time) on the humic acid (HA) removal efficiency and energy consumption. In this study, a new current supply method called alternating pulse current electrocoagulation-flotation (APC-ECF) process was proposed, and a detailed comparative optimization of four different ECF processes (direct current (DC)-simple electrode, DC-perforated electrode, pulse current-simple electrode, and pulse current-perforated electrode) was conducted within the framework of Taguchi-based experimental design methodology. According to scanning electron microscopy (SEM), the morphology of electrode surfaces with APC and perforated electrode showed less disordered (irregular) pores and a regular structure of aluminum compared to the DC, which confirmed the difference in the corrosion rates. Moreover, the proposed APC-ECF method led to the production of less dewatered and dense sludge. The results of the performance analysis revealed that the APC with a perforated electrode provided 3.2-fold lower energy consumption and 2.5-fold lower aluminum consumption compared to the DC with a simple electrode. Considering the expenses associated with power consumption and sludge disposal costs for the electrocoagulation unit, the experimental findings corroborated that the proposed APC-ECF process could be used as a promising and cost-effective technology in water treatment for the removal of HSs. [ABSTRACT FROM AUTHOR]

A novel application of artificial neural networks (ANN) combined with Taguchi orthogonal experimental design methodology (27 runs, 3 levels, 6 factors) was introduced for modeling and optimization of a new alternating pulse current electrocoagulation-flotation (APC-ECF) process for the removal of humic acid (HA) from aqueous media. Two different ANN architectures, such as multilayer perceptron (MLP NN) and generalized feed forward (GFF NN), were proposed and trained to describe the nonlinear behavior of a laboratory-scale batch APC-ECF reactor. Various operating parameters, such as initial HA concentration (C0), initial pH (pH0), electrical conductivity (EC0), current density (CD), and number of pulses (Npls), were used as inputs for the proposed networks, and the HA removal was selected as the output. According to the goodness-of-fit criteria, the computational results showed that the single hidden-layered GFF NN (5:6:1), where a sigmoid axon transfer function was used at its hidden layer and its output layer was trained by the Levenberg–Marquardt algorithm, showed the best performance (R2 = 0.999, MSE = 0.00006). For the optimal conditions of C0 = 42 mg/L, pH0 = 6.63, CD = 24.3 A/m2, EC0 = 856 μS/cm, and Npls = 3, the maximum HA removal was obtained based on the predicted outputs of the best ANN model (GFF NN). The results of the computational analysis clearly corroborated that ANN integrated design of experiments (DOE)-based modeling was rapidly and effectively used for predicting the optimum performance of a complex electrochemical process in removal of HA from water using aluminum electrodes in monopolar arrangement. [ABSTRACT FROM AUTHOR]

• A new alternating pulse current electrocoagulation-flotation process is introduced. • APC-ECF system is first modeled for removal of humic acid from water using ANN/DOE. • About 100% of HA is removed from water with an energy consumption of 1.08 kWh/kg HA. • ANN/DOE-based approach can describe behavior of a complex electrochemical process. A novel application of artificial neural networks (ANN) combined with Taguchi orthogonal experimental design methodology (27 runs, 3 levels, 6 factors) was introduced for modeling and optimization of a new alternating pulse current electrocoagulation-flotation (APC-ECF) process for the removal of humic acid (HA) from aqueous media. Two different ANN architectures, such as multilayer perceptron (MLP NN) and generalized feed forward (GFF NN), were proposed and trained to describe the nonlinear behavior of a laboratory-scale batch APC-ECF reactor. Various operating parameters, such as initial HA concentration (C 0), initial pH (pH 0), electrical conductivity (EC 0), current density (CD), and number of pulses (N pls), were used as inputs for the proposed networks, and the HA removal was selected as the output. According to the goodness-of-fit criteria, the computational results showed that the single hidden-layered GFF NN (5:6:1), where a sigmoid axon transfer function was used at its hidden layer and its output layer was trained by the Levenberg–Marquardt algorithm, showed the best performance (R 2 = 0.999, MSE = 0.00006). For the optimal conditions of C 0 = 42 mg/L, pH 0 = 6.63, CD = 24.3 A/m2, EC 0 = 856 μS/cm, and N pls = 3, the maximum HA removal was obtained based on the predicted outputs of the best ANN model (GFF NN). The results of the computational analysis clearly corroborated that ANN integrated design of experiments (DOE)-based modeling was rapidly and effectively used for predicting the optimum performance of a complex electrochemical process in removal of HA from water using aluminum electrodes in monopolar arrangement. [ABSTRACT FROM AUTHOR]

The potential of maize silk powder (MS) as a natural, widely available and low-cost agricultural waste in order to adsorb methylene blue (MB) from an aqueous solution has been studied. The adsorbent surface morphology has been studied using SEM and FTIR. The effect of operating conditions such as contact time, solution pH and initial MB concentration and the important frequently missed parameters such as salt effect (using NaCl and Na2HPO4), temperature effect (for ΔH°, ΔG° and ΔS°), solution pH and detailed error analysis have been determined. A rate study indicated the process followed pseudo-second order kinetics. The adsorption equilibrium was modeled for best fit using ten commonly-used isotherm models and the Jovanovic equation gave the best correlation of the experimental data. [ABSTRACT FROM AUTHOR]

In Section 2.3 on page 105, it was stated that: "Two L-shaped aluminium electrodes were embedded in the reactor in unipolar mode with an effective surface area of 100cm SP 2 sp at 1cm distance from each other, and 20 pores with a diameter of 4mm were created on the surface of each electrode." In Section 3.3.2 on page 109, it was stated that: "At the beginning of the process, the removal efficiency of HA versus time is increased with a steep slope, so that the highest HA removal rate in experiments shown in Fig. This sentence should be replaced by: "At the beginning of the process, the removal efficiency of HA versus time is increased with a steep slope, so that the highest HA removal rate in experiments shown in Fig. [Extracted from the article]