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Go to Editorial ManagerThe depleting of the conventional sources of energy and the excess use of HCF components lead to the need for new techniques both for conservation of energy sources for the future and for decreasing the its harmful effects on the environment. This study investigated the adsorption capabilities of activated carbon. The adsorption of methanol on this substance was tested for their application in the adsorption refrigeration system based on solar energy._x000D_ Adsorption refrigeration system has been designed and manufactured with the energy source being solar energy. Methanol/activated carbon pairs have been used in experiments. The present work focused on the performance of the adsorption refrigeration system considering the temperature attained in the evaporator and the cooled spaced cabinet. The amounts of activated carbon used was (8 kg), while the amount of methanol were (1, 1.25, and 1.5) kg. The experiments were done in different days of the year. The amount of adsorption of methanol (as a result of decreasing the evaporator and cooled spaced temperature) was found to depend on the generator pressure and its increase as the primary generator pressure decreases. The best mass of methanol used was (1 kg) which give the lowest temperature obtained at the evaporative surface was ( 3.4 oC ) at the day ( 4/4/2017 ). The results shown that even in cloudy days there is a benefit from using such a system because the temperature attained is enough to start the adsorption process. The lowest temperature obtained at the evaporative surface was (3.4 oC) at the day (4/4/2017) for methanol mass of (1 kg) at an opening time of the valve between the evaporator and the generator (9:30am). The increase of methanol amount used in the experiment led to a good decrease in temperature attained in cooled spaced, but this is related to the time of connecting the evaporator and generator.
The adsorption characteristics of Nickel (II) onto Iraqi Bentonite clay from aqueous solution have been investigated with respect to changes in pH of solution, adsorbent dosage, contact time and temperature of the solution. The maximum removal efficiency of Nickel (II) ions is 96% at pH=6.5 and exposure to 100 g/L adsorbent. For the adsorption of Nickel (II) ions, the Freundlich isotherm model fitted the equilibrium data better than the Langmuir isotherm model. Experimental data are also evaluated in terms of kinetic characteristics of adsorption and it was found that the adsorption process for Ni+2 ions follows well pseudo-second-order kinetics. Thermodynamic functions, the change of free energy (?G°), enthalpy (?H°) and entropy (?S°) of adsorption are also calculated for Nickel (II) ions. The results show that the adsorption of the Nickel (II) ions on Iraqi Bentonite is feasible and exothermic at (20-50) °C.
The adsorptions of copper ions from aqueous solution by can papyrus were studied using batch and continuous adsorption. It has been improved surface area and efficiency of the cane papyrus using urea and thiurea at different concentrations through stirring in period of time with mixer. Results proved that cane papyrus very well in the adsorption of metal through the study of important variables and influences such as the contact time, pH in addition to the initial concentration. It was found that the effect of pH at 6 to 7 better than acid or base solution also found that the best time for adsorption to reach equilibrium is 90min and there is no effect of temperature significantly on the results observed, studied the effect of weight of the cane where found that 0.4g best weight. After treatment with urea and thiurea the results improved from the 56% removal by natural cane, 61% for urea modified and 68% for thiurea modified. For continuous adsorption the results shows that when the flow rate increase in constant bed of adsorbent the breakthrough decrease. As well as the best curve was obtained using a cane modified with thiurea weighing 2.5g in a continuous flow rate where the breakthrough curve is start from 25min to 175min. The results was applied to Langmuir and Freundlich adsorption isotherms, the results fitted will to both at correlation coefficients 0.971 and 0.9066 for Langmiur and Freundlich respectively. Pseudo second order was applied and gives better results for adsorption where R2 is 0.9941 while for pseudo first order R2 is 0.136.
The heavy metals are considered dangerous pollutants which harm health and environment. The adsorption process is the cost effective process to get-rid of heavy metal efficiently. In this study, the adsorption bed of Nickel is simulated by using COMSOL Multiphysics to find the effect of different operating parameters namely; flow rate, temperature and pollutant concentration on adsorption bed efficiency. The modeling of non-isothermal adsorption bed based on experimental isotherms kinetic of previous work is developed too. The results showed that the optimal conditions to generate maximum removal efficiency of heavy metal were at 50?C inlet temperature, 0.1 M inlet concentration, and 80 ml/min flow rate to achieve removal values higher than 50 % of long operation period time.
The efficiency of adsorption using copper nanocomposite catalysts for the removal of lead ions from aqueous solution was studied. Nano copper and its nanocomposition were prepared in laboratory in very accurate conditions. After preparing samples, the samples were analyzed using XRD and SEM and that shows very good morphology of catalytic performance and has nano sized of crystalline shape. In order to study the efficiency of these catalysts, all samples were tested using adsorption process. The preparing samples show very good efficiency for lead removing from aqueous solution, and reach maximum removal efficiency 96% for 0.05g of adsorbents at pH 10, otherwise increasing or decreasing the pH would give undesirable results for all samples. Langmuir isotherm fitted better than Freundlich isotherm for adsorption of lead.
The intention of this study was to explore the efficiency and feasibility of adsorption of Reactive Blue dye (H3R) used in textile industries using Raw wheat straw (RWS) and Modified wheat straw (MWS) as a low-cost adsorbent. Wheat straw was modified using cationic surfactant (CTAB) to study the improvement of dye removal. The properties of Raw and Modified wheat straw are studied by means of Fourier transform infrared (FTIR) and scanning electron microscope (SEM) analyses to determine the functional groups and the nature of their surface. Continuous experiments were done by fixed-bed column to study the characteristics of the breakthrough curve using different bed heights and flow rates. Results showed that the breakthrough time increases with increasing bed height and decreasing flow rate, in turn results into higher removal capacity. Results also showed a higher flow rate lead a lower adsorption capacity due to insufficient residence time. Bed depth service time model (BDST), Adam-Bohart and Thomas models were used to predict the breakthrough curves and to determine the adsorption capacity of the column. The highest bed capacity of 12.95 and 32.2 mg/g for MWS was obtained using 10 mg/L, 10 cm bed height at 10 mL/min and 30 mL/min respectively.
In the present work, the agricultural wastes which are wheat bran and raw okra waste used as adsorbent material for adsorption of cadmium and copper ions from wastewater .The effect of adsorption variable which include initial pH of solution , agitation speed, agitation time, initial concentration of cadmium and copper ions, and amount of adsorbent material were investigated in a batch process in order to obtain the maximum ions removal from wastewater .The results obtained from experimental investigation show that the percentage removal of metal ions increases with increasing pH and agitation speed until a maximize value after that it decreased with increasing pH and agitation speed. Also increases with increasing amount of adsorbent material and agitation time until a maximize value then reach a constant value approximately , and decreasing with increasing metal ions concentration .The maximum removal percent of cadmium and copper ions were 85.8% and 52.7 % respectively which obtained at pH equal 5.0, agitation speed 150 revolution per minute, agitation time 105 minute , metal ion concentration 40mg /L ,and adsorbent amount 1.5gm when using wheat bran as adsorbent material ,while obtained the maximum removal percent of cadmium and copper ions were 81.7% and 47.8 % which obtained at pH equal 6.0, and pH equal 5.0 respectively , agitation speed 150 revolution per minute, agitation time 90 minute ,metal ion concentration 40 mg /L ,and adsorbent amount 1.5gm when using okra waste as adsorbent material. From above result the wheat bran and okra waste was a best adsorbent material for removal cadmium and copper ions from wastewater but wheat bran slightly more effective than okra waste._x000D_
The purpose of this study is to investigate the potential of biochar derived from Peganum harmala (Pgh) seeds as an adsorbent material for wastewater treatment. Biochar is a cost-efficient, ecologically friendly, and effective bio-sorbent for a wide range of pollutants in wastewater. Researchers are investigating the production of biochar from novel biomass sources. Phosphoric acid (H3PO4) was utilized in a chemical activation technique to produce biochar at various concentrations (20%, 30%, and 40%). The pyrolysis process lasted three hours at 600°C in a tube furnace with an inert nitrogen gas atmosphere. Elemental analysis, Brunauer-Emmett-Teller (BET) nitrogen adsorption, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), The biochar was characterized using several techniques, including elemental analysis, X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) nitrogen adsorption, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The findings demonstrate the significant potential of Pgh seed-derived biochar as an inexpensive and ecologically acceptable sorbent material. A large surface area (691.58 m2g−1) was achieved at 600◦C for three hours with 40% H3PO4 activation.
In this paper, the efficiency of six different types of corrosion inhibitors used in Basrah drinking water tanks was assessed using a potentiostatic test method. The mechanism of adsorption of silicate and phosphate inhibitors in AISI 316 stainless steel surfaces and the effects of different water components in inhibitors are discussed in detail. The values of corrosion rate obtained from the Potentiostatic test showed that the protection against corrosion in the presence of inhibitors is better compared to the case of absence of inhibitors. The results of the six types of corrosion inhibitors tested showed that the inhibitory efficacy is higher below the temperatures 45oC, but when raise the temperature above 45oC the inhibitory efficiency becomes to decrease. Also, the test results indicated that the corrosion inhibitor involves silicate products provided more inhibited efficiency compared to the phosphate inhibitor alone or used the combined silicate/phosphate corrosion inhibitor. The inspection of the surface of the tested samples using optical methods shows that the pitting corrosion is demonstrated on the specimen surfaces after testing with or without inhibitors.
Fourier transformation Infrared spectroscopy (FTIR) has been used to characterize and measure the concentration of acid sites (Si-OH-Al groups) in NaH-13 X Zeolites. Ion exchange was followed by dealumination to get (28, 40, 65, 85.8 and 97.5 Wt. %) of NaH-13 X Zeolites samples. The conclusion of homogeneity of OH groups was obtained by analysis of Fourier transformation infrared spectroscopy absorption bands of OH groups after adsorption and desorption of Ammonia. It found that there were different acid sites on a broader absorption (3,800-3,000 cm-1) corresponds to hydroxyl groups of the less acidic Brønsted acid sites approximately at 3464cm-1 and the more acidic at 3441cm-1 and Lewis acid sites was found at 1636 cm-1 which is few and weak acid sites . It can be conclusion that concentrations of OH groups increased with increasing the exchange degree and delamination. The concentration of acid sites in samples were calculated from stretching frequencies and extinction coefficients of OH bands, also the frequency shift ??OH = 23 cm-1 which was due to the hydrogen bonding of OH groups with ammonia in 97.5 % NaH-13 X Zeolites. Knowing the acidity of catalyst is important for the reactions which required acidic surface.
In this work, model fuel (Thiophene in hexane) was treated for sulfur removal by adsorptive desulfurization method using modified bentonite with sodium (Na-B) adsorbent. Batch and continuous mode were used in this study. Several operating parameters such as initial thiophene concentration of 250 to 2000 mg/L , adsorbent dose 0.1 to 0.8g/ml were studied for sulfur removal %. Also a comparison between raw and modified bentonite was performed in this study. In continuous mode, a packed bed of Na-B adsorbent column was used at constant initial thiophene concentration and liquid hourly space velocity (LHSV) to study the breakthrough curve of thiophene. The results showed that Na-B adsorbent was better than raw bentonite in removal of sulfur components. The removal percentages was 67,75,87,and 91% for 500 mg/L initial thiophene concentration using adsorbent dose o.1, 0.2, 0.4 and 0.8g/ml respectively , and 87, 75, 57, and 53% for adsorbent dose of 0.2 g/ml using initial thiophene concentration of 250, 500, 1000, and 2000 mg/L respectively. It was concluded that when increase the dose of adsorbent, the removal of sulfur increase , and when increase the initial concentration the removal decrease.
Providing a clean and high quality drinking water to both rural as well as urban areas is a great challenge by itself, adding to it the large volume requirements of such water at high population areas means a very high cost for such industry because mainly of the cost of expensive commercially available adsorbent used in this process. This led inhabitants of the remote and/or rural areas to use less quality water with all its risks and health challenges. In this study, a locally collected rice husk is tested to be used as an alternative adsorbent to the expensive common commercial ones. Parameters like adsorbent dosage, initial concentration of turbidity, and pH level were tested to investigate their effects on the process. Treatment of synthetic turbid water was done after changing these parameters to measure the effect of each parameter alone and the results showed a set of parameters that can be used to achieve high efficiency of turbidity removal. The study concluded that rice husk can be used as a well cheap alternative adsorbent to reduce the river water turbidity due to its availability and low cost with a decent removal efficiency approaching 95%.
Industrial activities significantly affect the environment by releasing many organic pollutants, including industrial dyes, phenols and antibiotics, which produce wastewater. Effective removal of these substances from wastewater has appeared as a noticeable research field owing to its environmental significance. Exorbitant operational expenses and the potential generation of supplementary pollutants load conventional techniques like adsorption, membrane separation, and coagulation. Semiconductor-based photocatalysis has effectively degraded organic contaminants into less toxic or biodegradable compounds. The construction of robust visible-light-sensitive photocatalytic hybrids for environmental decontamination is an inspiring task for researchers. The exceptional photocatalytic performance of silver halides (AgX, where X is I, Cl, and Br) has recently attracted significant consideration as photocatalysts. Moreover, the combination of silver halides with other photo-active semiconductors to create efficient visible-light-driven photocatalyst heterojunctions has significantly promoted the broader application of the photocatalysis process with enhanced efficiency. Ag-silver halides/semiconductors heterojunctions have developed as crucial components in efficient composites for photocatalysis through surface plasmonic actions, helping with visible light absorption. The current study overviews the most recent Ag and silver halide-based composite photocatalysts. Additionally, it provides an essential understanding of their promoted photocatalytic performances and their main applications in organic pollutant degradation. Moreover, the photocatalytic mechanisms and environmental applications of AgI and composites were discussed.