جستجوی مقالات مرتبط با کلیدواژه "کربن فعال" در نشریات گروه "مهندسی آب"

Dyes are one of the most important industrial environmental pollutants, and therefore their removal from industrial wastewater is very important. The malachite green is a very toxic dye for the environment and humans, therefore an economical and high-efficiency method to remove this dye from water solutions is necessary. In this study, the removal of malachite green was investigated using a economical and effective adsorbent, in which activated carbon from date kernel was used. Activated carbon from date kernel was modified by Fe3O4 magnetic nanoparticles and calcium oxide. The properties and characteristics of these adsorbents were investigated using FTIR, VSM, TGA, XRD and SEM analyzes. Parameters affecting the adsorption process such as pH, adsorbent dosage, contact time and initial concentration of malachite green were optimized. Equilibrium and kinetic study of adsorption process was performed using common models. The results showed optimal conditions for adsorption of malachite green using the adsorbent are: initial concentration equal to 10 mg/l, pH=7, contact time equal to 20 minutes, adsorbent dose for AC, AC/Fe3O4 and AC/Fe3O4/CaO equal to 3, 3 and 2 g/l, respectively. The Freundlich model also has a higher ability to describe process equilibrium behavior and the pseudo-second-order kinetics model has a good ability to express reaction kinetics. The Langmuir adsorption capacity of malachite green by the AC, AC/Fe3O4 and AC/Fe3O4/CaO was determined to be 50.9 mg/g, 85.7 mg/g and 107.4 mg/g respectively. The desorption and reuse ability of AC/Fe3O4/CaO was investigated up to 8 steps, which showed that the adsorbent has the ability to be reused several times in the adsorption process. The results showed that modification of activated carbon with magnetic Fe3O4 nanoparticles and calcium oxide increases its adsorption efficiency and makes it a suitable adsorbent for commercialization.

One of the hazardous compounds for humans and the environment is polycyclic aromatic hydrocarbons, which are the naphthalene of the precursor of two-ring aromatic hydrocarbons. These compounds are carcinogenic and toxic, they cause anemia and damage to the retina and are also toxic to plants and aquatic animals, these compounds have been identified as priority pollutants by the World Health Organization, yet these compounds are difficult to remove by biological methods. This study was performed in batch in vitro where the effect of parameters such as retention time 15, 30, 45, 60, 90 and 120 minutes, concentration of multi-walled carbon nanotubes and activated carbon from coconut skin 0.1, 0.25, 0.5, 0.75, 1 and 2 g/L), solution concentration 1, 5, 10, 15, 20, 50 and 100 mg/L and pH 3, 4, 5, 6, 7 and 8 the concentration of 10 mg/L naphthalene solution in naphthalene removal was investigated. Experimental data of adsorption equilibrium with different Langmuir and Freundlich adsorption isotherm models are evaluated and analyzed with adsorption kinetics by comparing R2 coefficient of analysis and analyzed by excel software. Maximum naphthalene adsorption on both carbon nanotubes and activated carbon nanotube adsorbent at initial concentration of 10 mg/L naphthalene and adsorbent dose equal to 0.75 g/L at pH=7 is an appropriate time to achieve maximum naphthalene adsorption;the balance mode is 90 minutes. The adsorption mechanism is consistent in both adsorbents of Langmuir adsorption isotherm and their coefficient of determination in carbon nanotubes is (R²=0.9589) and in coconut shell activated carbon (R²=0.9319). and both adsorbents are from adsorption synthetics second-degree followers. Multiwalled carbon nanotubes and activated carbon from coconut skin due to their small size, high cross-sectional area as a result of high reactivity, as an adsorbent for removal of naphthalene from water. And the nanotube has a higher absorption than activated carbon from the coconut skin, so it is considered as a better adsorbent because of its affordability and availability.

The combination of magnetic nanoparticles with other adsorbents not only does not affect their magnetic properties, but also leads to the formation of adsorbents that improve the refining process.The aim of this study was synthesis of magnetic activated carbon by Fe3O4 and investigating its efficiency in adsorption of Lead from aqueous solutions. Magnetic adsorbent prepared by the method of sequestration and physical characteristics and structure of synthesized absorbent were determined by XRD and TEM. To remove the Lead from aqueous solutions, the Box-behnken design (BBD) of response surface methodology (RSM) was employed for optimizing all parameters affecting the adsorption process. The studied parameters were pH(5-9), temperature (25-45 0C) and the amount of adsorbent (0.5-2 g). 15 experimental runs were calculated by using BBD. The optimal condition for removal of Lead by synthesis of magnetic activated carbon by Fe3O4 nanoparticles were pH=7, 450C temperature and The 2 g of adsorbent. Kinetic studies of the adsorption process specified the  efficiency of the pseudo second-order kinetic model and showed the optimal time was15 min, respectively. The maximum percentage of Lead removed after 90 min was 86.87%. The adsorption isotherm waswell fitted to Longmire model. The study showed that magnetic activated carbon has a high potential for Remove Lead. Therefore, it is believed that magnetized active carbon by keeping its physical and surface properties could be a suitable method to solve some related problems includingseparation and filtration.

Phenol is one of the aromatic hydrocarbons with high toxicity and adverse health effects on living beings. It can be found in wastewater from industries such as chemical and petrochemical industries and oil refineries. The aim of this study is to evaluate the c hybrid process of Fenton oxidation and adsorption on removal of phenol from water. In this paper an experimental study in laboratory scale is implemented. Variables such as: concentration of Fe2+, H2O2, pH, activated carbon and time are tested in order to impact on the rate of removal of phenol in water. Finally, optimal conditions for the removal of phenol through the hybrid process of adsorption test and oxidation Fenton test is introduced. Results show that 95, 94 and 96 percent of Phenol is removed, respectively with initial concentration of 50,150 and 250 mg/L by combination of adsorption test and Fenton test, in pH = 3, Fe2+ = 10 mg/L, H2O2 = 150 mg/L, activated carbon = 2.5 g/L and time = 90 min. It can be concluded that hybrid process of adsorption and oxidation of Fenton can be used as a suitable method to reduce of Phenol from water.

The presence of nitrate in groundwater resources has instigated increasing concerns among both managers and users of, especially, drinking and sanitation water. From among the different nitrate removal methods, the adsorption method has attracted more attention thanks to its high removal efficieny and economical operation. Commercial activated carbon ranging in mesh size from 30‒40 was utilized to remove nitrate from an aqueous solution. In order to enhance nitrate uptake, different acid, alkaline, and cationic surfactant post-treatments were examined. Alkaline post-treatment followed by cationic surfactant modification was found to yield the best efficiency. FTIR, SEM, and N2 adsorption/desorption were carried out to determine the physical and chemical properties of activated carbon. Kinetic tests revealed that adsortption reached its equilibrium state after 12 hiurs and that the pseudo-second order and Freundlich models. Based on the Langmuir model, maximum adsorption capacity was found to be 15.34 and pH had an insignificant effect on nitrate adsorption. Moreover, the highest decline in nitrate adsorption was observed in the presence of sulfate followed by chloride, phosphate, and carbonate. Based on the results obtained, the modified activated carbon accompanied by washing with sodiuym hydroxide and modified cationic surfactant post-treatment might be recommended for use in adsorption processes as a promising innovative technology for nitrate removal from drinking water.

This study is an experimental investigation of sulfate removal efficiency using iron nanocomposites on graphene oxide and activated carbon beds. The graphene oxide used was synthesized according to the Hummer method during which process graphene oxide and activated carbon were added. The effects of various parameters including adsorbent content, pH, and contact time on adsorption were investigated. Furthermore, the data were subjected to kinetic studies. Results revealed that the highest absorption rates of 84% and 62% were achieved for iron on the graphene oxide and activated carbon beds, respectively, when 0.06 g of the adsorbent was used at pH =11 over a contact time of 9 hours. It was also found that the kinetic pseudo-second-order model best fit the data. Finally, the results indicated that the two environmentally-friendly adsorbents have a good potential for removing sulfate from aqueous solutions.

In this study, the adsorption of active carbon derived from waste sesame seeds coated with polyvinyl alcohol (AC/PVA) was investigated for removing red 198 and blue 19 reactive dyes from textile effluents. The batch process was carried out to identify such parameters as pH, adsorbent dose, contact time, and initial dye concentration involved in the dye removal adsorption capacity of AC/PVA. Also, batch kinetic and isotherm experiments were conducted. Results indicated that the maximum dye removal was obtained in an acidic pH over 90 min of contact time and that adsorption rates followed the pseudo-second-order kinetics. Blue and red dye concentrations were determined using the spectrophotometric method at 590 and 517 nm, respectively. It may be concluded that AC/PVA is capable of removing blue and red reactive dyes and can be used as an efficient, cheap, and accessible adsorbent for treating textile effluents.

This study investigates both the capacity of pure polyurethane foam in adsorbing oil contaminants and the effect of its structural modification by activated carbon (composite) on the performance of the foam in terms of adsorption capacity and efficiency. To this end, pure polyurethane foam and its activated carbon composites were synthesized and crude oil removal tests were conducted with initial crude oil concentrations of 20 to 280 g/L. Experimental results showed that the optimum weight percentage of activated carbon introduced into the foam structure was 5% wt, which enhanced adsorption capacity by up to 21%. The presence of activated carbon in the foam structure increased the hydrophobicity of the composites while, at the optimal concentration of activated carbon, its adsorption efficiency increased by up to 73% for an initial oil concentration of 20 g/L. Equilibrium studies showed that the Langmuir and Redlich-Peterson isotherms were the fitting ones for oil removal adsorption description. Chemical recovery of the sorbents used was performed using oil solvents (toluene and petroleum ether), which confirmed enhancement in both adsorption efficiency and capacity of the pure sorbent foam and the composite adsorbent.

Activated carbon is a valuable product that has many industrial and environmental applications and therefore it’s production from cheap wastes, is an economic-environmental action. According to the multiplicity of factors that affect adsorption properties of produced activated carbon, the design of experiments via Taguchi method was used to identify the main factors and optimization of activated carbon production. Based on the results, the impregnation ratio and activating reagent have the greatest impact on iodine number of almond shell activated carbon compared to other factors. In this study, activated carbon was produced with iodine number equal to 1331 mg/g, by optimization of chemical activation almond shell. Adsorption experiments showed that adsorption kinetics of dissolved petroleum hydrocarbons on activated carbon derived has followed from second-order reaction. Near to 95% of adsorption was happened during the first 30 minutes of process. Also the adsorption isotherm data were well followed from Freundlich isotherm model.

Wastewater containing dyes can be dangerous and toxic. Therefore, simple and efficient treatment methods are investigated by the researchers. The main purpose of this research is preparing adsorbent from residuals and studying the performance of dye removal from aqueous solution. For this purpose, activated carbon based on pomegranate residual was prepared by phosphoric acid (37%) activation and was used to remove reactive blue 19 from aqueous solution. In addition to characterization of the activated carbon (morphological and textural properties of activated carbon), effect of operation parameters such as contact time, initial pH, adsorbent dose and initial dye concentration were evaluated on the dye removal. The surface area (SBET) of the activated carbon was determined as 572.53 m2/g and the maximum dye removal efficiency (98.16%) was observed at 5 minutes contact time, initial pH 11, 3.5 gr/L the adsorbent and 300 mg/L initial dye concentration. Finally, adsorption isotherms (Langmuir, Freundlich and Temkin) and kinetic studies (the pseudo first-order, pseudo-second-order, Elovich and intraparticle diffusion kinetic models) studies showed the adsorption process follows a Langmuir isotherm equation (R2=0.955) and the pseudo-second order kinetic model (R2=0.997).

The most important environmental pollutants are heavy metals in industrial wastewater effluents. Nickel is one of the toxic heavy metals which its high concentration causes skin allergy, heart disease and various cancers. So removal of this element from industrial effluent is of prime concern and necessary. The main purpose of this study is to compare kinetics and isotherms of nickel uptake by activated carbon (AC), sawdust (SD), hazelnut shell (SH) and almond shells (AH). Adsorbents are initially prepared to remove nickel from solutions with concentrations 2.5 to 125 mg/l. pH test results showed that maximum absorption using AC, SH, SD and AH obtained at pH 6, 6, 6 and 7 respectively. Kinetics experiments showed that maximum absorption equilibrium time at concentration of 5 mg/l of AC, SH, SD and AH occur at 60, 75, 120 and 150 minutes respectively. Kinetic models fitting results showed that for sawdust and hazelnut shells, Lagergern model and for activated carbon and peanut shell Ho et al. model are suitable and have the lowest error and highest correlation coefficient at 95 percent confidence level. The results also revealed that rate of Nickel adsorption follows this order: AH

Keywords: Adsorption, Activated Carbon, Hazelnut Crust, Shell Peanuts, Sawdust

Surface and groundwater resources are increasingly jeopardized by discharges from pharmaceutical, chemical, and detergent plants. The high pollutant load of the effluents from these industries requires specific treatments. The objective of this research was to study and compare the nanofiltration and adsorption hybrid system with the plain nanofiltration system in wastewater treatment.For this purpose, a pilot nanofiltration system with a capacity of 7.6 m3/d using 1 and 5 micron filters and a FILMTEC NF90-4040 membrane was used in the first phase of the study. In the second phase, granular activated carbon cartridges were used. Inluent and effluent discharges as well as the COD removal were measured in both systems under variable times and organic load conditions. The results showed that COD removal efficiency was higher in the hybrid system than in the plain naonofiltration one. In the hybrid system, the Maximum in the hybrid system, the COD removal efficiencies achieved for organic loads of 1000, 2000, and 3000 mg/L were 99%, 95.86%, and 92.93%, respectively. The same values for the plain nanofiltration system were 87.34%, 50%, and 29.41%, respectively. It was found that polarization and membrane fouling decreased both the effluent flow and the COD removal efficiency with time. Fouling of the membrane was, however, lower in the hybrid system compared to the plain nanofiltration; thus, the hybrid system was associated with higher values of COD removal and delayed membrane fouling.