Rozita Moradi; Majid Mohadesi
Abstract
The aim of this research was to separate mercury from gold refining wastewater using activated carbon (AC) from natural shells. To this end, walnut and coconut shells were used as the main source of AC. The characterizations of both ACs were compared by FTIR, BET, and SEM analyses. The FTIR results revealed ...
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The aim of this research was to separate mercury from gold refining wastewater using activated carbon (AC) from natural shells. To this end, walnut and coconut shells were used as the main source of AC. The characterizations of both ACs were compared by FTIR, BET, and SEM analyses. The FTIR results revealed interactions between the solute and the functional groups on the adsorbent surface. According to the BET results, the mean pore diameter (MPD) of AC from coconut shells (CSAC) was smaller than that derived from walnut shells (WSAC). The specific surface areas for CSAC and WSAC were 1069.1 and 119.6 m2/g, respectively. SEM results revealed that the porous texture of ACs emanates from their cellular structure. This research further studied the impact of operational parameters “adsorbent dose” (0.3-3.8 g/L), “pH” (2-9), and “residence time” (10-120 min) on mercury removal. Under optimal operational conditions, the mercury removal rate reached 97% (for WSAC) and 93% (for CSAC). Kinetic model assessments revealed the highest agreement between the experimental data and the pseudo-first-order (PFO) model. Both adsorbents were regenerable, with their performance (compared to fresh adsorbents) exceeding 90% after each regeneration.
Mukhtar Dhajir Shubber; Mohammed Kadhum Al kasser; Daryoush Yousefi Kebria
Abstract
The study aims to show the role of pH value and the feasible mechanisms that affect the adsorption capacity by the theoretical concept and experimental work. The protonation, ionization, hydrophobicity, dissociation, precipitation, hydrolysis, hydroxylation, electrical repulsion or interaction, ion exchange, ...
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The study aims to show the role of pH value and the feasible mechanisms that affect the adsorption capacity by the theoretical concept and experimental work. The protonation, ionization, hydrophobicity, dissociation, precipitation, hydrolysis, hydroxylation, electrical repulsion or interaction, ion exchange, and complexation and chelating are effective mechanisms that have been studied theoretically to show their essential role in the absorption process and how they are affected by the pH value. Moreover, using varied pH values (2, 4, 6.5, 9, 11, and 13) to verify experimentally the role of the studied mechanisms on the adsorption capacity utilizing the recycled bentonite waste as adsorbent to adsorb the heavy metals, methylene blue dye, and engine oil as adsorbates from aqueous solution. It was apparent that the pH solution has an influential role in the adsorption capacity and from the difficulty in predicting the effect without making the experimental investigations due to the nature of the adsorbent and adsorbate that affected the ten mechanisms where the pH of the high adsorption capacity for heavy metal was alkaline (>11) and for the methylene blue and engine oil was neutral(≈ 6.5).
Fatemeh Hoveidamanesh; Zahra Beagom Mokhtari-Hosseini; Toktam Shenavaei Zare; Hashem Akhlaghi
Abstract
The existence of arsenic in water is one of the main problems of the world, especially in developing countries. One of the methods suggested for removal of arsenic is the use of adsorbents. In this study, natural Sabzevar zeolite was modified with HDTMA-Br, HCl, NaCl and FeCl3.6H2O for the adsorption ...
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The existence of arsenic in water is one of the main problems of the world, especially in developing countries. One of the methods suggested for removal of arsenic is the use of adsorbents. In this study, natural Sabzevar zeolite was modified with HDTMA-Br, HCl, NaCl and FeCl3.6H2O for the adsorption of arsenic. It was found that zeolite modified with FeCl3.6H2O was best for the removal of arsenic. Contact time (h), pH, zeolite particle size (mesh) and amount of zeolite (g) as the important parameters were optimized by Taguchi method. The optimum values for these parameters were contact time of five h, pH=3, and 100-200 mesh particles. The maximum adsorption capacity of 99.5% was obtained at optimum condition. Reactivation of the modified zeolite using HCl showed that the reactivated zeolite adsorbed 98% of the arsenic, a slight decrease compared to the original material. The presented adsorption process is a green and economical process for removing arsenic from water and contaminated groundwater.
Ali Hosseinian Naeini
Abstract
It is becoming increasingly evident that numerous nations are teetering on the edge of a crisis induced by environmental issues, posing threats to the well-being of both humans and animals. Diverse factors characterized by vivid hues, like air pollution and fluctuations in water quality, contribute to ...
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It is becoming increasingly evident that numerous nations are teetering on the edge of a crisis induced by environmental issues, posing threats to the well-being of both humans and animals. Diverse factors characterized by vivid hues, like air pollution and fluctuations in water quality, contribute to a multitude of issues and can adversely impact the environment at large. Given the current heightened demand for freshwater reserves, there exists a more urgent necessity to devisepragmatic approaches for treating wastewater. One prospective technique entails the utilization of polymer nanocomposites to avert impurities such as heavy oils, cosmetics, and oil-based paints. These adjuncts leverage state-of-the-art nanotechnologies, such as carbon nanotubes and activated carbon, showcasing significant efficacy in refining water resources. Concurrently, striking a balance between financial viability and environmental benevolence. Moreover, the employment of adsorption methodologies proves to be highly efficacious in decontaminating tainted water reservoirs by eradicating organic pollutants, employing an array of substances as adsorbents for this purpose. Exemplars of thriving adsorbents include dendritic polymers MXenes, which manifest distinctive characteristics like heightened surface area and porosity, coupled with enhanced reusability and structural integrity when amalgamated with polysaccharides. Generally, the application of polymer nanocomposites as adsorbents for organic contaminants holds promising potential in innovating novel, cost-effective techniques for purifying water and shielding against chemical impurities.
Ahmad Sabzali; Fatemeh Mohammadi; Zeynab Sadeghzadeh; Mona Eghbali Gharehbelagh
Abstract
Treatment of pharmaceutical wastewaters, especially compounds resistant to biological degradation, is very important, and various methods have been introduced to treat such wastewaters on a laboratory and experimental scale. A new designed reactor consisting advanced oxidation and activated carbon adsorption ...
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Treatment of pharmaceutical wastewaters, especially compounds resistant to biological degradation, is very important, and various methods have been introduced to treat such wastewaters on a laboratory and experimental scale. A new designed reactor consisting advanced oxidation and activated carbon adsorption was undertaken for treating toxic pharmaceutical wastewater containing p-Nitrochlorobenzene (pNCB) in the pilot scale. During Paracetamol manufacturing some pNCB may be remained without any chemical changes depended on reaction condition. The effluent from reactor may have some concentration of the pNCB, which can cause a lot of problems if discharged directly into the environment. Organic substance and pNCB concentration of the influent and effluent of the reactor was investigated for 30 days in two phases. The first phase of operation included the achievement of stable conditions and the second phase included the survey of removal efficiency by changing the operational parameters. Raw wastewater was entered directly into the reactor through overhead distillation column in process of Paracetamol manufacturing. The wastewater flow ranged from 3.8 to 16 m3/day during two phases. The average efficiencies for the pNCB concentration removal were 99.4 % for the phase I and 98.0% for phase II. COD removal efficiency of 97.8% was achieved for the reactor. Although oxidation process is effective in removing pNCB, but the most effect was related to absorption process. This study demonstrates that application of Simultaneous ozonation and adsorption processes is effective for treating wastewater containing pNCB.
Sajad Abdi; Hossein Hazrati; Seyed Majid Abdoli
Abstract
Over recent decades, there has been a documented rise in natural organic matter (NOM) levels in surface waters globally, adversely affecting drinking water treatment processes. This study is focused on employing adsorption techniques to explore the removal of proteinaceous NOM from an aqueous solution. ...
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Over recent decades, there has been a documented rise in natural organic matter (NOM) levels in surface waters globally, adversely affecting drinking water treatment processes. This study is focused on employing adsorption techniques to explore the removal of proteinaceous NOM from an aqueous solution. A chitosan/polyacrylamide (chitosan/PAM) hydrogel was synthesized through a multi-step procedure involving chitosan and acrylamide solutions preparation, polymerization initiation, mixing, gelation, purification, and drying. The Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) techniques were employed to characterize the synthesized chitosan/PAM hydrogel, examining its structural and morphological features. Adsorption experiments were conducted to assess performance of chitosan/PAM hydrogel adsorbent for the removal of bovine serum albumin (BSA) from aqueous solutions. Various physical parameters including temperature, time, pH, initial BSA concentration, and adsorbent dosage were examined in batch experiments. The adsorption capacity of chitosan/PAM hydrogel for BSA and removal percent of BSA was found 617 mg/g and 77.2 % at 6 h under optimum conditions (T= 25ºC and pH=7) with kinetic studies indicating a best fit with the pseudo-1st-order model. Isotherm studies demonstrated that the Temkin isotherm model best fitted with experimental BSA adsorption data (R2 > 0.99). The findings underscore the efficacy of the developed adsorbent in efficiently removing natural proteins. Furthermore, the experimental results indicate that the adsorption capacity of the chitosan/PAM hydrogel augmented with rising temperature and initial BSA concentration.
Zahra Fadaei; Kurosh Rad-Moghadam; Parvaneh Pakravan
Abstract
This study explored the efficacy of a cost-efficient activated carbon (AC) derived from natural bitumen through chemical activation with phosphoric acid. The objective was to evaluate bitumen-based activated carbon (AC) potential as a novel adsorbent by integrating Cu (NO3)2.3H2O onto AC for the removal ...
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This study explored the efficacy of a cost-efficient activated carbon (AC) derived from natural bitumen through chemical activation with phosphoric acid. The objective was to evaluate bitumen-based activated carbon (AC) potential as a novel adsorbent by integrating Cu (NO3)2.3H2O onto AC for the removal of harmful dyes from water-based solutions. Assessments of the adsorption capabilities of Cu@AC were conducted using representative samples of cationic and anionic dyes, namely methylene blue (MB) and methyl orange (MO). The incorporation of Cu onto the AC, leading to the formation of Cu@AC, resulted in a significant enhancement of the adsorption capacity of AC. The adsorption capacity of Cu@AC was measured using Brunauer–Emmett–Teller (BET) and iodine number measurements, with the most optimal Cu@AC sample exhibiting a BET surface area of 611 m2/g. Surface chemical properties were analyzed through FT-IR spectroscopy, while the microstructure of the produced Cu@AC was examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The efficiency of the adsorption process was influenced by factors such as pH, initial dye concentration, adsorbent dosage, and contact time. The most effective processing conditions for dye removal were determined as pH 11 for MB and pH 5 for MO, with an initial concentration of 25 mg/L, a 0.5 g/L adsorbent dosage, and a temperature of 333 K for a duration of 90 min. Under these optimized conditions, removal efficiencies exceeded 90% for MO and 80% for MB. The results demonstrated that Cu@AC has the potential to function as a cost-effective alternative to commercially available activated carbons for efficiently eliminating dyes from contaminated water.
Behzad Hossieni; Somayeh Sohrabi; Faranak Akhlaghian
Abstract
Inexpensive and new adsorbents, which are produced by processing the abundant agricultural by-products, can provide an efficient solution for a cleaner environment. The occurrence of heavy metals in water may pose a significant threat to human health. In this work, the processed date kernels are used ...
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Inexpensive and new adsorbents, which are produced by processing the abundant agricultural by-products, can provide an efficient solution for a cleaner environment. The occurrence of heavy metals in water may pose a significant threat to human health. In this work, the processed date kernels are used to remove chromium (VI) and iron (III) from water. The XRD, FTIR, SEM, VSM and EDX techniques are used to characterize the adsorbents. The equilibrium adsorbent dose for iron is 2 g/L while for chromium (VI) it is 4 g/L and the equilibrium time is 20 min. Moreover, acidic conditions favored the adsorption for both targets. The adsorption experiments showed that the kinetics of adsorption of chromium (VI) and iron (III) on date kernel powder fitted the pseudo-second-order model. The optimum adsorption capacities for iron (III) and chromium (VI) are 10.5 mg/g and 0.66 mg/g, respectively. In the meantime, the remarkable efficiency of the date kernel-based adsorbent for iron (III) removal paves the way for designing new magnetic adsorbents.
Samaneh Salmani; Hassan Rezaei; Hajar Abyar
Abstract
Agricultural product processing generates substantial quantities of agricultural waste and their disposal has become a critical concern, threatening human health and the environment. The pyrolysis process is an upgrading technology for producing valuable products from waste feedstocks. Hence, the potential ...
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Agricultural product processing generates substantial quantities of agricultural waste and their disposal has become a critical concern, threatening human health and the environment. The pyrolysis process is an upgrading technology for producing valuable products from waste feedstocks. Hence, the potential of eco-friendly biochar derived from cotton waste was comprehensively investigated for methylene blue removal. The cotton-based biochar contained various pore sizes and functional groups on the surface verified by SEM and FTIR analyses. The impacts of adsorbent dose, methylene blue concentration, temperature, pH, and contact time on the adsorption of methylene blue were assessed to highlight the efficiency of the cotton-based biochar. The results revealed >90% removal under 10 mg/l methylene blue concentration, 0.7 g adsorbent dose, pH of 6, and contact time of 60 min at a temperature of 20 ⁰C. The adsorption isotherm was well-fitted with the Freundlich model, indicating the multilayer methylene blue adsorption. The adsorption process was chemisorption and endothermic based on kinetic and thermodynamic modeling. Summing up, it can be suggested that the cotton-based biochar can be easily and efficiently applied for methylene blue removal from aqueous solutions, and further investigations are required to modify its specific surface area by a green synthesis approach.
Mahboobeh Zarei; Majid Baghdadi; Fatemeh Yazdian; Nasser Mehrdadi
Abstract
In this study, an optimized composite of expanded graphite /g-C3N4 /phenylenediamine was synthesized and characterized by SEM, FESEM, EDS, XRD, and BET methods.The composite was prepared with an optimized combination using response surface methodology (RSM) as a proper adsorbent for eliminating heavy ...
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In this study, an optimized composite of expanded graphite /g-C3N4 /phenylenediamine was synthesized and characterized by SEM, FESEM, EDS, XRD, and BET methods.The composite was prepared with an optimized combination using response surface methodology (RSM) as a proper adsorbent for eliminating heavy metals from water samples. The evaluation of the final adsorbent was accomplished by removing metal ions like Pb2+ and Cd2+. Under the optimum adsorption conditions for Pb2+ and Cd2+ (pH:5, adsorbent dosage:2 g/L, and Time:60 min), elimination efficiencies were 78.4% for Cd2+ and 71.35% for Pb2+. pH was the most important factor that influenced the adsorption rate. A short contact time for maximum removal efficiency was reported because of the porous structure of the constructed composite. As a result of the absorptive construction, the equilibrium showed a satisfactory agreement with the Freundlich model. The kinetic evaluations showed that the adsorption process of both heavy metals fitted the pseudo-second-order model. Furthermore, the results of thermodynamic studies indicated that the adsorption was an endothermic and spontaneous process. A series of regeneration experiments (5 cycles) was directed to evaluate the adsorbent reusability. The results presented that it was a suitable adsorbent for heavy metal uptake from aquatic solutions.
Nazanin Niknezhad; Neda Azimi; Shahin Ahmadi
Abstract
The purpose of this study was numerical and experimental investigations on the influence of ultrasound on Cr (VI) removal from aqueous solution by adsorption onto activated carbon nanoparticles. The effect of key factors on Cr (VI) elimination like media pH, absorbent mass, initial concentration of Cr ...
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The purpose of this study was numerical and experimental investigations on the influence of ultrasound on Cr (VI) removal from aqueous solution by adsorption onto activated carbon nanoparticles. The effect of key factors on Cr (VI) elimination like media pH, absorbent mass, initial concentration of Cr (VI) and the location of ultrasound transducers were considered. To perform CFD modeling of ultrasound propagation, the vibrations of 1.7 MHz piezoelectric transducers (PZTs) were defined based on the dynamic mesh model. The experimental results indicated that by pH raising from 2 to 8, Cr (VI) removal efficiency had a decreasing trend and at pH=8, it had the lowest value. The adsorption rate increased by augmentation in the adsorbent mass (AM) due to the enhancing its specific surface area. In comparison with using a shaker, ultrasound showed lower needed contact time for Cr (VI) elimination at identical conditions. In addition, CFD results depicted that the acoustic streams were induced in the direction of ultrasound propagation, which is caused to reach the better mixing and Cr (VI) removal efficiency. Finally, the experimental data were adopted with the Langmuir and Freundlich isotherms. The comparison of these models showed that both models were well suited to experimental findings and the data compatibility with Langmuir model was greater.
Zakie Rostami; Masoud Rahimi; Neda Azimi
Abstract
In this study, Ni+2 removal from aqueous solution was investigated by concurrent usage of Fe3O4 nanoparticles and a high frequency ultrasound (1.7 MHz). In addition to Ni+2 removal, presence of the high frequency ultrasound led to being cooled photovoltaic (PV) module. Studied variables were pH and adsorbent ...
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In this study, Ni+2 removal from aqueous solution was investigated by concurrent usage of Fe3O4 nanoparticles and a high frequency ultrasound (1.7 MHz). In addition to Ni+2 removal, presence of the high frequency ultrasound led to being cooled photovoltaic (PV) module. Studied variables were pH and adsorbent dose (AD). Results indicated that the Ni+2 removal efficiency increased with an increase in the pH ranging from 2 to 9. Furthermore, the Ni+2 removal efficiency boosted by an increase in the AD. However, no significant enhancement in Ni+2 removal efficiency was observed at the AD above 9 g. Generally, the maximum Ni+2 removal efficiency was about 79 % for contact time of 50 min at pH=9 and AD=9 g in the presence of ultrasound. At the efficient condition (pH=9, AD=9 g and contact time=50 min), using ultrasound showed 16-20 % enhancement in Ni+2 removal efficiency compared to no ultrasound usage. From heat transfer view, it was observed that propagation of 1.7 MHz ultrasound into nanofluid significantly has cooled the photovoltaic (PV) module. Moreover, an increase in concentration of nanofluid (AD) showed a positive effect on reduction of heat from the PV module surface and maximum generated power. Obtained data demonstrated that agitating nanofluid by 1.7 MHz ultrasound decreased temperature of the PV module up to 15.5 % compared to no cooling system.
Mohammad Hesam Falsafi; Mohsen Moghaddas; Jafarsadegh Moghaddas
Abstract
In this study, removal of heavy metals from synthetic wastewater has been investigated using silica aerogel-activated carbon composite. The synthesized adsorbent was characterized by FE-SEM, FTIR and BET techniques. The effect of amine functional groups embedded on the surface of silica aerogel-activated ...
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In this study, removal of heavy metals from synthetic wastewater has been investigated using silica aerogel-activated carbon composite. The synthesized adsorbent was characterized by FE-SEM, FTIR and BET techniques. The effect of amine functional groups embedded on the surface of silica aerogel-activated carbon 0.5 wt. % composite, optimal initial pH of removal of ions, impact of initial concentration of the solution containing heavy metal ions, adsorbent amount and contact time on removal percentage of ions were investigated. The results showed the optimal pH of 8, optimal adsorbent amount of 0.3 g for the removal of cadmium ion and 0.06 g for the removal of lead ion and optimal contact time of 80 min for cadmium and 60 min for lead ions. Adsorption data were investigated using Langmuir and Freundlich isotherms and maximum adsorption capability for cadmium and lead was obtained at 38.16 and 175.44 mg/g adsorbent, respectively.
Tahereh Mansouri Jalilian; Neda Azimi; Shahin Ahmadi
Abstract
The effect of ultrasound on cobalt adsorption from aqueous solution onto Fe3O4/Bentonite nanocomposite is investigated. Two layouts of using shaker and sono-separator equipped with ultrasound are considered. The effect of pH on Co(II) ions removal is investigated. Co(II) removal rate increased with increasing ...
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The effect of ultrasound on cobalt adsorption from aqueous solution onto Fe3O4/Bentonite nanocomposite is investigated. Two layouts of using shaker and sono-separator equipped with ultrasound are considered. The effect of pH on Co(II) ions removal is investigated. Co(II) removal rate increased with increasing pH from 2 to 10, and it reduced after pH=10. For the shaker, the contact time (t) of 50 min is selected as the most effective case. However, for sono-separator the maximum value of Co(II) removal rate is 78% at t=10 min, and it decreased after 10 min. The effect of the adsorbent mass (AM) is investigated and Co(II) removal increased by increasing the specific surface area of the adsorbent. The highest Co(II) removal rates are 83.3% and 86% for the shaker and the sono-separator, respectively. No significant increase for Co(II) removal is observed for increasing AM more than 3 g. The effect of the transducer locations and initial concentration of Co(II) ions (C0) at pH=10 and AM =3 g are investigated. The results showed that the activation of all transducers had the best performance. Initially, with increasing C0 from 0.05 to 0.1 g/L, Co(II) removal rate increased from 84% to 86%, respectively, but with increasing C0 from 0.1 to 0.15 and 0.2 g/L, cobalt removal has been decreased. Finally, the experimental data are adopted with Langmuir and Freundlich isotherms. The comparison of these models showed that both models are well suited to experimental data and data compatibility with the Langmuir model is greater.
Amir Hossein Salimi; Sayed Farhad Mousavi; Saeed Farzin
Abstract
Rivers serve as one of the main sources of water supply. Human activities, salts in the soil and rocks and urban runoffs, as well as air contaminants, lead to contamination of river water. In this research, Gamasiab river, which is the upstream of Karkheh river, was selected as a case study. Sixteen ...
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Rivers serve as one of the main sources of water supply. Human activities, salts in the soil and rocks and urban runoffs, as well as air contaminants, lead to contamination of river water. In this research, Gamasiab river, which is the upstream of Karkheh river, was selected as a case study. Sixteen stations were selected along this river to determine the sulfate content of water samples. Samples were taken from these stations according to the guidelines (ISO 5667-5, 1991). The samples were then transferred to laboratory and were filtered using nanoparticles of natural clinoptilolite. The X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) andFourier-Transform Infrared Spectroscopy (FTIR) images were taken to determine the properties of the adsorbents. The images indicated that the selected methods for preparation of the nanoparticles were correctly implemented. After examining the filtered samples, the adsorption efficiency was 95% for clinoptilolite. Whatman filter paper 42 was used for desorption of the natural nano-clinoptilolite. Adsorption isotherm of the natural clinoptilolite was Freundlich with a determination coefficient of R2=0.918. By using Design Expert software and assumption of two pH factors and adsorbent to contaminant ratios (D/C), optimum adsorption points were found and theoretical adsorption values were calculated as well. Results showed that the optimum adsorption points for clinoptilolite were pH = 9.51 (mg)adsorbent/(mg/l)initial and D/C=18.91(mg)adsorbent/(mg/l) initial. Comparison of the adsorbent function indicated that clinoptilolite had good performance in removal of sulfate ion from river water samples.
Danial Nayeri; Seyyed Alireza Mousavi; Azadeh Mehrabi
Abstract
In this study, oxytetracycline removal from aqueous solution by activated carbon prepared using corn stalks has been investigated. The adsorbent was characterized using Fourier transform infrared spectrophotometer (FTIR) and scanning electron microscope (SEM). The effects of main variables; adsorbent ...
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In this study, oxytetracycline removal from aqueous solution by activated carbon prepared using corn stalks has been investigated. The adsorbent was characterized using Fourier transform infrared spectrophotometer (FTIR) and scanning electron microscope (SEM). The effects of main variables; adsorbent dose, contact time, pH, and initial oxytetracycline concentration on the efficiency of adsorption efficiency were investigated. Results confirmed the effects of main variables and the maximum removal of antibiotic (99.9 %) achieved at initial concentration of 10 mg/L, pH of 9, and contact time of 60 min, when adsorbent dose was 1.5 g. The results of isotherm and kinetic studies showed that the oxytetracycline adsorption onto activated carbon prepared from corn stalks follows Freundlich isotherm (R2 = 0.98) and pseudo-second order kinetic model (R2 = 0.99). The maximum adsorption capacity of oxytetracycline was 522.6 mg/g. In brief, the activated carbon that has been prepared from corn stalks as low cost, non-toxic and environment friendly adsorbent shows a good ability for removal of oxytetracycline form water and wastewater.
Behnaz Jalili; Seyed Mehdi Borghei; Vahid Vatanpour; Christopher Sarkizi
Abstract
Wastewater reuse has been attracted a lot of attention in recent years especially in places with low water availability. The effluents that were considered to be discharged are now could be used as potential sources of reusable water. In this study, variables affecting the removal of ethylene glycol ...
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Wastewater reuse has been attracted a lot of attention in recent years especially in places with low water availability. The effluents that were considered to be discharged are now could be used as potential sources of reusable water. In this study, variables affecting the removal of ethylene glycol (EG) by adsorption on granular activated carbon (GAC) from the synthetic wastewater solutions were optimized by response surface methodology (RSM) using a central composite design. The investigated factors were temperature, EG concentration, contact time, activated carbon amount and granular size. Adsorption kinetic was also studied and an acceptable correlation between Langmuir model and experimental data was observed. As a result, a modified third degree equation was proposed and used to find the optimized condition. The maximum adsorption was achieved at 27.7 ºC with 0.8 g of 20-30 mesh activated carbons for an EG feed concentration of 135 mg/L at 210 minutes.
Saideh Fatemeh Shafeii Darabi; Nader Bahramifar; Mohamad Ali Khalilzadeh
Abstract
Present study explored the adsorptive characteristics of eosin Y and red X dyes from aqueous solution onto treated rice husk (TRH). Batch experiments were carried out to determine the influence of parameters likes initial pH, adsorbentdose, contact time and initial concentration on the removal of eosinY ...
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Present study explored the adsorptive characteristics of eosin Y and red X dyes from aqueous solution onto treated rice husk (TRH). Batch experiments were carried out to determine the influence of parameters likes initial pH, adsorbentdose, contact time and initial concentration on the removal of eosinY and red X. The adsorption kinetics of the two dyes on to TRH was found to follow pseudo-second-order kinetic model. The equilibrium data is successfullyfitted to the Freundlich and Langmuir adsorption isotherm for eosin Y and red X, respectively. The thermodynamic analysis indicated that the sorption process was endothermic for eosin Y and exothermic for red X and the negative value of change in Gibbs free energy indicated feasible and spontaneous adsorption for both of dyes. The removal percentage of dyeswas about 90% (q e= 31.72 mgg-1) for eosin Y and 93.44 % for red X(qe=32.44mgg-1). Overall, the present findings suggest that this environmentally friendly, efficient and low-cost adsorbent is useful for the removal of eosin Y and red X from aqueous solution.
Arezoo Fereidonian Dashti; Mohd Nordin Adlan; Hamidi Abdul Aziz; Ali Huddin Ibrahim
Abstract
The creation of very pollute palm oil mill waste water has resulted in semiserious environmental hazards. The reason for the current study is to test the optimal removal of ammonia nitrogen (NH3-N) from palm oil mill waste water by filtration using inexpensive filters media in place of current methods, ...
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The creation of very pollute palm oil mill waste water has resulted in semiserious environmental hazards. The reason for the current study is to test the optimal removal of ammonia nitrogen (NH3-N) from palm oil mill waste water by filtration using inexpensive filters media in place of current methods, to remove ammonia nitrogen from palm oil mill effluent. A series of batch and column studies were conducted using a different particle size of limestone (4, 12 and 20 mm) at various filtration rates of 20 ml/min, 60 ml/min and 100 ml/min. An experimental model design was conducted using Central Composite Design (CCD) in Response Surface Methodology (RSM). RSM was used to calculate the outcomes of process variables and their role in reaching ideal conditions. Equilibrium isotherms in this study were evaluated using the Langmuir and Freundlich isotherm. Using statistical analysis, the NH3–N removal model proved to be very significant with very low probability values (0.0001). The column study showed that ideal NH3-N removal was attained using a lower flow rate and smaller sized limestone (LS). The ideal conditions found when using 4 mm limestone and a 20 ml/min flow rate. This resulted in 45.3% removal of NH3–N which was seen in the predicted model, and fit well with the laboratory results (45%). The adsorption isotherm data fit the Langmuir isotherm.
