Equilibrium and Kinetic Studies on the Removal of Reactive Red 2 Dye from an Aqueous Solution Using a Positively Charged Functional Group of the Nymphaea rubra Biosorbent     

Sahadevan Renganathan  Jayabalan Kalpana  Mahendradas Dharmendira Kumar  Manickam Velan 《洁净——土壤、空气、水》2009,37(11):901-907

Nymphaea rubra stem was used as a low cost and easily available biosorbent for the removal of Reactive Red 2 dye from an aqueous solution. Initially, the effects of biosorbent dosage (0.2–1.0 g L^–1), pH (1–6), and dye concentration (30–110 mg L^–1) on dye removal were studied. Batch experiments were carried out for biosorption kinetics and isotherm studies. The results showed that dye uptake capacity was found to increase with a decrease in biosorbent dosage. Equilibrium uptake capacity was found to be greatest at a pH value of 2.0, when compared to all other pH values studied. The equilibrium biosorption isotherms were analyzed by the Freundlich and Langmuir models. The equilibrium data was found to fit very well with the Freundlich isotherm model when compared to the Langmuir isotherm model. The kinetic data was analyzed using pseudo-first order and pseudo-second order kinetic models. From the results, it was observed that the kinetic data was found to fit the pseudo-second order kinetic model very well. The surface morphology of the stem of the N. rubra biosorbent was exemplified by scanning electron microscopy. Fourier transform infrared analysis was employed to confirm the existence of an amine group in the stem of N. rubra.  相似文献   

Equilibrium Uptake and Bioaccumulation of Basic Violet 14 Using Submerged Macrophyte Hydrilla verticillata     

Gopalakrishnan Saranya  Panneerselvam Saravanan  Mahendradas Dharmendira Kumar  Sahadevan Renganathan 《洁净——土壤、空气、水》2011,39(3):283-288

The percentage removal and uptake capacity of Basic Violet 14 using Hydrilla verticillata with living biomass was studied under batch conditions. The survival of H. verticillata was studied using the chlorophyll content in the living biomass. Bioaccumulation of Basic Violet 14 using H. verticillata was tested by varying the wet sorbent dosage (0.5–2.5 g), initial pH (3–8), and initial dye concentrations (5–25 mg L^?1). The results show that the plant was effectively accumulating the Basic Violet 14 dye. The uptake capacity of Basic Violet 14 dye was observed as 5.9 and 21.3 mg g^?1 at the initial dye concentration of 5 and 25 mg L^?1, respectively, for a biomass of 5 g L^?1 (wet weight) at pH 7.0 for 144 h. In general, the plant growth was found to be normal at lower concentrations and showed higher removal efficiency. It was also observed that removal efficiency of H. verticillata was found to decrease with increase in initial dye concentration. The biomass sample surface was analyzed using SEM imaging and functional groups present in the biomass were analyzed using FTIR. The equilibrium uptake capacity was analyzed by Langmuir and Freundlich isotherms. The equilibrium data was found to be fit well to both Langmuir and Freundlich isotherm models with higher coefficient of determination.  相似文献   

Adsorption Characteristics of Reactive Black 5 from Aqueous Solution onto Chitosan     

Tapan K. Saha  Nikhil C. Bhoumik  Subarna Karmaker  Mahmooda G. Ahmed  Hideki Ichikawa  Yoshinobu Fukumori 《洁净——土壤、空气、水》2011,39(10):984-993

Adsorption of reactive black 5 (RB5) from aqueous solution onto chitosan was investigated in a batch system. The effects of solution pH, initial dye concentration, and temperature were studied. Adsorption data obtained from different batch experiments were modeled using both pseudo first‐ and second‐order kinetic equations. The equilibrium adsorption data were fitted to the Freundlich, Tempkin, and Langmuir isotherms over a dye concentration range of 45–100 µmol/L. The best results were achieved with the pseudo second‐order kinetic and Langmuir isotherm equilibrium models, respectively. The equilibrium adsorption capacity (q_e) was increased with increasing the initial dye concentration and solution temperature, and decreasing solution pH. The chitosan flakes for the adsorption of the dye was regenerated efficiently through the alkaline solution and was then reused for dye removal. The activation energy (E_a) of sorption kinetics was estimated to be 13.88 kJ/mol. Thermodynamic parameters such as changes in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) were evaluated by applying the van't Hoff equation. The thermodynamics of reactive dye adsorption by chitosan indicates its spontaneous and endothermic nature.  相似文献   

Parameter Optimization of Activated Carbon Production from Agave sisalana and Punica granatum Peel: Adsorbents for C.I. Reactive Orange 4 Removal from Aqueous Solution     

Thambiannan Senthilkumar  Rajendran Raghuraman  Lima Rose Miranda 《洁净——土壤、空气、水》2013,41(8):797-807

In the present study, activated carbons were prepared from sisal fiber (Agave sisalana sp.) and pomegranate peel (Punica granatum sp.) using phosphoric acid as the activating agent. Both sisal fiber activated carbon (SFAC) and pomegranate peel activated carbon (PPAC) were characterized using methylene blue number, iodine number, BET surface area, SEM, and FTIR. The BET surface area of the SFAC and PPAC were 885 and 686 m²/g, respectively. The adsorption studies using C.I. Reactive Orange 4 dye on the SFAC and PPAC were carried out. The effects of time, initial adsorbate concentration, pH, and temperature on the adsorption were studied. The isotherm studies were carried and it was found that the Langmuir and Freundlich isotherms fit well for the adsorption of RO 4 on SFAC, while adsorption of RO 4 on PPAC is better represented by the Langmuir and Temkin isotherms. Adsorption kinetics of adsorption was determined using pseudo first order, pseudo second order, Elovich and intraparticle diffusion models and it was found that the adsorption process follows pseudo second order model. Thermodynamics parameters such as changes in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) were determined by using van't Hoff equation. The positive ΔH value indicates that RO 4 dye adsorption on SFAC and PPAC is endothermic in nature.  相似文献   

Assessment of the Biosorption Characteristics of a Spent Cottonseed Husk Substrate for the Decolorization of Methylene Blue     

Qi Zhou  Wenqi Gong  Dongjiang Yang  Chuanxin Xie  Yubiao Li  Xiafang Liu  Cuiping Bai  Rui Wang 《洁净——土壤、空气、水》2011,39(12):1087-1094

This study concentrates on the possible application of the spent cottonseed husk substrate (SCHS), an agricultural waste used after the cultivation of white rot fungus Flammulina velutipes, to adsorb methylene blue (MB) from aqueous solutions. Batch studies were carried out with variable initial solution pH, adsorbent amount, reaction time, temperature, and initial MB concentration. MB uptake was favorable at pH ranging from 4.0 to 12.0, and the equilibrium adsorption capacity of 143.5 mg g^?1 can be reached promptly within about 240 min. The combination analysis of FTIR and BET techniques revealed that the massive functional groups on the biosorbent surface, such as hydroxyl and carboxyl, were responsible for the biosorption of MB. It was found that adsorption data matched the pseudo‐second order kinetic and Langmuir isotherm models. Thermodynamic parameters of free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), obtained from biosorption MB ranging from 293 to 313 K, showed that the sorption experiment was a spontaneous and endothermic process. The study highlighted a new pathway to develop a new potential utilization of SCHS as a low‐cost sorbent for the removal of MB pollutants from wastewater.  相似文献   

Oreganum Stalks as a New Biosorbent to Remove Textile Dyes from Aqueous Solutions     

Ebru Mavioglu Ayan  Pelin Secim  Serhat Karakaya  Jale Yanik 《洁净——土壤、空气、水》2012,40(8):856-863

In the present study, Oreganum onites L. stalks in natural and chemically modified with HNO³ and H³PO⁴ used as adsorbent for removal of both acidic and basic dyes from waters. The adsorption was studied as a function of pH and contact time by batch method. All tested biosorbents were characterized by FT‐IR, scanning electron microscopy, and measuring the pH dependence of the zeta potential. The adsorption isotherms were fitted to Langmuir isotherm. The maximum adsorption capacity of dyes was 280.73 mg g^?1 for Basic Red 18, 147.06 mg g^?1 for methylene blue and 112.36 for Acid Red 111, which is comparable to that of other lignocellulosic materials. The modification process was considerably increased the biosorption capacity of lignocellulosic material, resulting in a 56–63% increase in the biosorption capacity of basic dyes and a 125% increase in the biosorption capacity of acidic dye. The present study illustrated that the most effective factors in the adsorption of basic dye were surface charge and acidic groups on lignocellulosic biosorbents, while non‐electrostatic forces as well as electrostatic forces were also effective in the adsorption of acidic dye. In conclusion, Oreganum stalks can be considered as a very prospective adsorbent for the removal of tested basic and acidic dyes.  相似文献   

Thorium(IV) removal from aqueous medium by citric acid treated mangrove endophytic fungus Fusarium sp. #ZZF51     

S.K. Yang  N. Tan  X.M. Yan  F. Chen  W. Long  Y.C. Lin 《Marine pollution bulletin》2013

Thorium(IV) biosorption is investigated by citric acid treated mangrove endophytic fungus Fussarium sp. #ZZF51 (CA-ZZF51) from South China Sea. The biosorption process was optimized at pH 4.5, equilibrium time 90 min, initial thorium(IV) concentration 50 mg L⁻¹ and adsorbent dose 0.6 g L⁻¹ with 90.87% of removal efficiency and 75.47 mg g⁻¹ of adsorption capacity, which is obviously greater than that (11.35 mg g⁻¹) of the untreated fungus Fussarium sp. #ZZF51 for thorium(IV) biosorption under the condition of optimization. The experimental data are analyzed by using isotherm and kinetic models. Kinetic data follow the pseudo-second-order model and equilibrium data agree very well with the Langmuir model. In addition, FTIR analysis indicates that hydroxyl, amino, and carbonyl groups act as the important roles in the adsorption process.  相似文献   

Removal of Cadmium from Aqueous Solution Using Castor Seed Hull: A Kinetic and Equilibrium Study   总被引：1，自引：0，他引：1  

Tushar Kanti Sen  Masita Mohammod  Saikat Maitra  Binay K. Dutta 《洁净——土壤、空气、水》2010,38(9):850-858

The effects of various parameters such as initial concentration, adsorbent loading, pH, and contact time on kinetics and equilibrium of adsorption of Cd²⁺ metal ion from its aqueous solution by castor seed hull (CSH) and also by activated carbon have been investigated by batch adsorption experiments. The amount of adsorption increases with initial metal ion concentration, contact time, solution pH, and the loading of adsorbent for both the systems. Kinetic experiments indicate that adsorption of cadmium metal ion on both CSH and on activated carbon consists of three steps – a rapid adsorption of cadmium metal ion, a transition phase, and an almost flat plateau region. This has also been confirmed by the intraparticle diffusion model. The lumped kinetic results show that the cadmium adsorption process follows a pseudo‐second order rate law. The kinetic parameters including the rate constant are determined at different initial metal ion concentrations, pH, amount, and type of adsorbent, respectively. The Langmuir and Freundlich adsorption isotherm models are used to describe the experimental data. The Langmuir model yields a better correlation coefficient than the other model. A comparison of the monolayer adsorption capacity (q_m) of CSH, activated carbon, and several other reported adsorbents has been provided. The value of separation factor (R_L) calculated from the Langmuir equation also gives an indication of favorable adsorption of the metal ion. From comparative studies, it has been found that CSH is a potentially attractive adsorbent than commercial activated carbon for cadmium metal ion (Cd²⁺) removal.  相似文献   

Adsorptive Removal of Acid Blue 15: Equilibrium and Kinetic Study     

N. Thinakaran  P. Baskaralingam  K. V. Thiruvengada Ravi  P. Panneerselvam  Subramanian Sivanesan 《洁净——土壤、空气、水》2008,36(9):798-804

Activated carbons prepared from sunflower seed hull have been used as adsorbents for the removal of acid blue 15 (AB‐15) from aqueous solution. Batch adsorption techniques were performed to evaluate the influences of various experimental parameters, e. g., temperature, adsorbent dosage, pH, initial dye concentration and contact time on the adsorption process. The optimum conditions for AB‐15 removal were found to be pH = 3, adsorbent dosage = 3 g/L and equilibrium time = 4 h at 30°C. The adsorption of AB‐15 onto the adsorbent was found to increase with increasing dosage. It was found from experimental results that the Langmuir isotherm fits the data better than the Freundlich and Temkin isotherms. The maximum adsorption capacity, Q_m (at 30°C) was calculated for SF1, SF2, and SF3 as 75, 125 and 110 mg g^–1 of adsorbent, respectively. It was found that the adsorption follows pseudo‐second order kinetics. The thermodynamic parameters such as ΔG°, ΔH°, and ΔS° were also evaluated. The activated carbons prepared were characterized by FT‐IR, SEM and BET analysis.  相似文献   

Malachite Green Removal from Aqueous Solution by the Peel of Cucumis sativa Fruit     

Thirumalisamy Santhi  Subbian Manonmani 《洁净——土壤、空气、水》2011,39(2):162-170

This study investigates the potential use of activated carbon prepared from the peel of Cucumis sativa fruit for the removal of malachite green (MG) dye from simulated wastewater. The effects of different system variables, adsorbent dosage, initial dye concentration, pH, and contact time were investigated and optimal experimental conditions were ascertained. The results showed that when the amount of the adsorbent increased, the percentage of dye removal increased accordingly. Optimum pH value for dye adsorption was 6.0. Maximum dye was sequestered within 50 min of the start of every experiment. The adsorption of MG followed the pseudo‐second‐order rate equation and fits the Langmuir, Freundlich, Dubinin–Radushkevich (D–R), and Tempkin equations well. The maximum removal of MG was obtained at pH 6 as 99.86% for adsorbent dose of 1 g/50 mL and 25 mg L^?1 initial dye concentration at room temperature. Activated carbon developed from the peel of C. sativa fruit can be an attractive option for dye removal from diluted industrial effluents since test reaction made on simulated dyeing wastewater showed better removal percentage of MG.  相似文献   

Biosorption of Methylene Blue from Aqueous Solution Using a Bioenergy Forest Waste: Xanthoceras sorbifolia Seed Coat     

Zengyu Yao  Lihua Wang  Jianhua Qi 《洁净——土壤、空气、水》2009,37(8):642-648

Xanthoceras sorbifolia seed coat (XSSC), a bioenergy forest waste, was used for the adsorption of methylene blue (MB) from aqueous solutions. The effects of adsorbent dosage, pH, adsorbate concentration and contact time on MB biosorption were studied. The equilibrium adsorption data was analyzed by Langmuir and Freundlich isotherm models. The results indicated that the Langmuir model provided the best correlation with the experimental data. The adsorption capacity of XSSC for MB was determined with the Langmuir model and was found to be 178.6 mg/g at 298 K. The adsorption kinetic data was modeled using the pseudo‐first order, pseudo‐second order, and intraparticle diffusion kinetic equations. It was seen that the pseudo‐second order equation could describe the adsorption kinetics, and intraparticle diffusion was not the sole rate controlling factor. Thermodynamic parameters were also evaluated. Standard Gibbs free energy was spontaneous for all interactions, and the biosorption process exhibited exothermic standard enthalpy values. The results indicated that XSSC is an attractive alternative for removing cationic dyes from wastewater.  相似文献   

Modification of MCM‐41 with Anionic Surfactant: A Convenient Design for Efficient Removal of Cationic Dyes from Wastewater     

Mohammad Ali Zanjanchi  Hassan Sajjadi  Majid Arvand  Ali Mohammad‐Khah  Bahram Ghalami‐Choobar 《洁净——土壤、空气、水》2011,39(11):1007-1013

The potential of MCM‐41 for the removal of cationic dyes from water solution was evaluated using sodium dodecyl sulfate (SDS) for the surface modification of this mesoporous material. Admicelle structures formed on the surface of the calcined MCM‐41 are capable of removing organic pollutants and cationic species from water environment. The structural, textural, and surface chemical characteristics of the prepared SDS‐modified MCM‐41 (SDS‐MCM‐41) were studied. The adsorption capacity of SDS‐MCM‐41 was evaluated for methylene blue (MB) as a target cationic dye. Equilibrium adsorption isotherm data were manipulated employing nonlinear regression analysis. The Langmuir, Freundlich, and Sips isotherm models were examined. The adsorption data were well fitted to both Langmuir and Sips isotherm models. The maximum adsorption capacity of SDS‐MCM‐41 for MB, based on Langmuir and Sips models, were 290.8 and 297.3 mg g^?1, respectively. Ethanol was found to be an effective solvent for partial regeneration of the adsorbent.  相似文献   

Removal of Congo Red from Aqueous Solution by Sorption on Organified Rectorite     

Yi Liu  Wenbo Wang  Aiqin Wang 《洁净——土壤、空气、水》2010,38(7):670-677

Batch sorption technique was carried out for the removal of anionic dye Congo red (CR) from aqueous solution using raw rectorite (R‐REC) and organified rectorite (CTA⁺‐REC) modified by cetyltrimethylammonium bromide (CTAB) as adsorbents. The effects of organification degree of CTA⁺‐REC as well as the process parameters including the pH of dye solution, sorption time, and initial dye concentration on adsorption capacity for CR were investigated and the sorption kinetics was also evaluated. The results showed that the sorption behaviors of R‐REC and CTA⁺‐REC for CR followed pseudo‐second‐order kinetic model and the sorption equilibrium data perfectly obeyed the Langmuir isotherm. The thermodynamic parameters including entropy of sorption (ΔS⁰), enthalpy of sorption (ΔH⁰), and Gibbs free energy of sorption (ΔG⁰) were obtained and analyzed. Fourier transform infrared study revealed that a chemisorption process occurred between CR and CTA⁺‐REC. REC modified by cationic surfactants showed the higher adsorption capacities for CR compared to R‐REC and in theory would be used as an efficient and promising adsorbent for the removal of anionic dyes in wastewater treatment.  相似文献   

The Seashell Wastes as Biosorbent for Reactive Dye Removal from Textile Effluents     

Daniela Suteu  Doina Bilba  Magdalena Aflori  Florica Doroftei  Gabriela Lisa  Marinela Badeanu  Teodor Malutan 《洁净——土壤、空气、水》2012,40(2):198-205

This study investigates structural and adsorption properties of the powdered waste shells of Rapana gastropod and their use as a new cheap adsorbent to remove reactive dye Brilliant Red HE‐3B from aqueous solutions under batch conditions. For the powder shells characterization, solubility tests in acidic solutions and X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), Fourier transform IR spectroscopy (FT‐IR) and thermogravimetric analyses were performed. The results revealed that the adsorbent surface is heterogeneous consisting mainly from calcium carbonate layers (either calcite or aragonite) and a small amount of organic macromolecules (proteins and polysaccharides). The dye adsorptive potential of gastropod shells powder was evaluated as function of initial solution pH (1–5), adsorbent dose (6–40 g L^?1), dye concentration (50–300 mg L^?1), temperature (5–60°C), and contact time (0–24 h). It was observed that the maximum values of dye percentage removal were obtained at the initial pH of solution 1.2, shells dose of 40 g L^?1, dye initial concentration of 50–50 mg L^?1 and higher temperatures; the equilibrium time decreases with increasing of dye concentration. It is proved that the waste seashell powder can be used as low cost bioinorganic adsorbent for dyes removal from textile wastewaters.  相似文献   

Adsorption Characteristics of Rhodamine B from Aqueous Solution onto Baryte     

Govindasamy Vijayakumar  Chang Kyoo Yoo  Kuppana Gounder P. Elango  Mahendiradas Dharmendirakumar 《洁净——土壤、空气、水》2010,38(2):202-209

Batch sorption experiments were carried out for the adsorption of the basic dye Rhodamine B from aqueous solution using baryte as the adsorbent. The effect of adsorbent dosage, temperature, initial dye concentration and pH were studied. Adsorption data were modeled using first and second order kinetic equations and the intra particle diffusion model. Kinetic studies showed that the adsorption process followed second order rate kinetics with an average rate constant of 0.05458 g mg^–1 min^–1. Dye adsorption equilibrium was attained rapidly after 30 min of contact time. The equilibrium data was fitted to the Langmuir, Freundlich and Tempkin isotherms over a dye concentration range of 50–250 mg/L. The adsorption thermodynamic parameters showed that adsorption was an exothermic, spontaneous and less ordered arrangement process. The adsorbent, baryte, was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed that baryte has good potential for the removal of Rhodamine B from dilute aqueous solution.  相似文献   

Adsorption of Thallium(I) Ions Using Eucalyptus Leaves Powder     

Hossein Dashti Khavidaki  Hossein Aghaie 《洁净——土壤、空气、水》2013,41(7):673-679

Using batch method, the adsorption of thallium(I) ions from aqueous solutions on eucalyptus leaves powder, as a low cost adsorbent, was studied. The effect of various modification of considered adsorbent on the adsorption percentage of Tl(I) is an important feature of this study. The results showed that the unmodified and acidic modified adsorbent are the poor adsorbents for the Tl(I) ions while basic modified adsorbent is a suitable adsorbent. Also, the effect of some experimental conditions such as solution initial pH, agitation speed, contact time, sorbent dosage, temperature, particle size, and thallium initial concentration was studied. The results showed that the adsorption percentage depends on the conditions and the process is strongly pH‐dependent. The satisfactory adsorption percentage of Tl(I) ions, 81.5%, obtained at 25 ± 1°C. The equilibrium data agreed fairly better with Langmuir isotherm than Freundlich and Temkin models. The value of q_m that was obtained by extrapolation method is 80.65 mg g^?1. Separation factor values, R_L, showed that eucalyptus leaves powder is favorable for the sorption of Tl(I). The negative values of ΔH⁰ and ΔS⁰ showed that the Tl(I) sorption is an exothermic process and along with decrease of randomness at the solid–solution interface during sorption, respectively.  相似文献   

Batch and Continuous Design of a Full‐Scale Treatment Facility for Removing Dissolved Natural Organic Matter     

Bulent Sari  Ali Erdem Oztas  Olcayto Keskinkan  Cagatayhan Bekir Ersu 《洁净——土壤、空气、水》2021,49(1)

Batch and continuous flow adsorption experiments are carried out and the design of a full‐scale facility for removing dissolved natural organic matter (DNOM) from Catalan Lakewater is demonstrated. The adsorption efficiency is proportional to the temperature and the amount of adsorbent unlike pH increase. The highest DNOM removal rate is obtained at 35 °C, pH 4, and an adsorbent amount of 0.8 g L^?1. Optimum contact time for batch studies is 60 min at equilibrium. Correlation constants (r) of Langmuir and Freundlich isotherms are 0.8905 and 0.9739, respectively. Based on the Freundlich isotherm, the highest adsorption capacity (q_max) obtained is 2.44 and 6.01 mg DNOM/g granulated activated carbon (GAC) for raw and enriched water, respectively. Consequently, the effects of adsorbent amount, bed depth, empty bed contact time, and organic loading on removal performance are investigated in the rapid small‐scale column test (RSSCT) columns. The targeted effluent concentration of 1 mg DNOM/L can easily be achieved in the columns. At the design capacity of the facility, 15 adsorption columns with dimensions of 7 m height, 4.33 m diameter, and 22 days of operation cycle are required to remove DNOM from raw water.  相似文献   

Removal of Arsenic from Simulated Groundwater Using GAC‐Ca in Batch Reactor: Kinetics and Equilibrium Studies     

Prasenjit Mondal  Bikash Mohanty  Chandrajit Balo Majumder 《洁净——土壤、空气、水》2012,40(5):506-514

This paper deals with kinetics and equilibrium studies on the adsorption of arsenic species from simulated groundwater containing arsenic (As(III)/As(V), 1:1), Fe, and Mn in concentrations of 0.188, 2.8, and 0.6 mg/L, respectively, by Ca²⁺ impregnated granular activated charcoal (GAC‐Ca). Effects of agitation period and initial arsenic concentration on the removal of arsenic species have also been described. Although, most of the arsenic species are adsorbed within 10 h of agitation, equilibrium reaches after ～24 h. Amongst various kinetic models investigated, the pseudo second order model is more adequate to explain the adsorption kinetics and film diffusion is found to be the rate controlling step for the adsorption of arsenic species on GAC‐Ca. Freundlich isotherm is adequate to explain the adsorption equilibrium. However, empirical polynomial isotherm gives more accurate prediction on equilibrium specific uptakes of arsenic species. Maximum specific uptake (q_max) for the adsorption of As(T) as obtained from Langmuir isotherm is 135 µg/g.  相似文献   

Adsorption of Pb(II) Ions from Aqueous Solutions by Date Bead Carbon Activated with ZnCl2     

Mohammed Danish  Rokiah Hashim  Mohd Rafatullah  Othman Sulaiman  Anees Ahmad  Govind 《洁净——土壤、空气、水》2011,39(4):392-399

This study reports on the adsorption characteristics of Pb(II) ions from aqueous solutions using ZnCl₂‐activated date (Phoenix dactylifera) bead (ADB) carbon with respect to change in adsorbent dosage, initial pH, contact time, initial concentration, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo‐second‐order kinetic model. Thermodynamic parameters, enthalpy change (ΔH° = 55.11 kJ/mol), entropy change (ΔS° = ? 0.193 kJ/mol/K), and Gibbs free energy change (ΔG°) were also calculated for the uptake of Pb(II) ions. These parameters show that adsorption on the surface of ADB was feasible, spontaneous in nature, and endothermic between temperatures of 298.2 and 318.2 K. The equilibrium data better fitted the Langmuir and Freundlich isotherm models than the D–R adsorption isotherm model for studying the adsorption behavior of Pb(II) onto the ADB carbon. It could be observed that the maximum adsorption capacity of ADB was 76.92 mg/g at 318.2 K and pH 6.5.  相似文献   

Dye Removal from Colored Textile Wastewater by Poly(propylene imine) Dendrimer: Operational Parameters and Isotherm Studies     

Bagher Hayati  Niyaz Mohammad Mahmoodi  Mokhtar Arami  Firoozmehr Mazaheri 《洁净——土壤、空气、水》2011,39(7):673-679

This paper deals with the removal of textile dyes from aqueous solutions by poly(propylene imine) dendrimer (PPI). Direct red 80 (DR80), Acid Green 25 (AG25), Acid Blue 7 (AB7), and Direct Red 23 (DR23) were used as model dyes. The effects of operational parameters on dye removal such as dendrimer concentration, dye concentration, salt (inorganic anions), and pH have been studied at 25°C. The Langmuir and Freundlich isotherm models were investigated. In addition, dye desorption of dendrimer was studied. The results indicated that acidic pH supported the adsorption of dyes by dendrimer. Furthermore studies of dye concentration and salt effects exhibited that dye removal percentage by dendrimer was decreased. It was found that the isotherm data of DR80, AG25, and DR23 followed Langmuir isotherm and isotherm data of AB7 followed Freundlich isotherm models. Desorption tests showed that maximum dye releasing of 76.5% for DR80, 84.5% for AG25, 87% for AB7, and 93% for DR23 were achieved in aqueous solution at pH 12. Based on the data of present study, one could conclude that the dendrimer being an environmentally friendly adsorbent with relatively large adsorption capacity might be a suitable alternative for elimination of dyes from colored textile wastewater.  相似文献