Lead removal from aqueous solutions by natural Greek bentonites

Clay Minerals ◽  
2013 ◽  
Vol 48 (5) ◽  
pp. 771-787 ◽  
Author(s):  
A. Bourliva ◽  
K. Michailidis ◽  
C. Sikalidis ◽  
A. Filippidis ◽  
M. Betsiou

AbstractThree bentonite samples (B1, B2, B3) from Milos Island, Greece, were investigated by XRD, AAS, DTA-TG, FTIR and specific surface area measurement techniques. A laboratory batch study has been performed to investigate the adsorption characteristics of lead ions (Pb2+) onto natural bentonite samples. The effect of various physicochemical factors that influence adsorption, such as solution pH (2–6), adsorbent dosage (1–10 g L–1), contact time (20–360 min), and initial metal ion concentration (5–150 mg L–1) was studied. A number of available models like the Lagergren pseudo first-order kinetic model, the pseudo second-order kinetic model and intra-particle diffusion were utilized to evaluate the adsorption kinetics. The adsorption of Pb2+ was modelled with the Langmuir, Freundlich and D-R isotherms. The maximum Pb2+ adsorption capacities for B1, B2 and B3 were 85.47 mg g–1, 73.42 mg g–1 and 48.66 mg g–1, respectively.

2017 ◽  
Vol 19 (3) ◽  
pp. 120-129 ◽  
Author(s):  
Wojciech Konicki ◽  
Małgorzata Aleksandrzak ◽  
Ewa Mijowska

Abstract In this study, the adsorption of Ni2+ and Fe3+ metal ions from aqueous solutions onto graphene oxide (GO) have been explored. The effects of various experimental factors such as pH of the solution, initial metal ion concentration and temperature were evaluated. The kinetic, equilibrium and thermodynamic studies were also investigated. The adsorption rate data were analyzed using the pseudo-first-order kinetic model, the pseudo-second-order kinetic model and the intraparticle diffusion model. Kinetic studies indicate that the adsorption of both ions follows the pseudo-second-order kinetics. The isotherms of adsorption data were analyzed by adsorption isotherm models such as Langmuir and Freundlich. Equilibrium data fitted well with the Langmuir model. The maximum adsorption capacities of Ni2+ and Fe3+ onto GO were 35.6 and 27.3 mg g−1, respectively. In addition, various thermodynamic parameters, such as enthalpy (ΔHO), entropy (ΔSO) and Gibbs free energy (ΔGO), were calculated.


2010 ◽  
Vol 62 (8) ◽  
pp. 1888-1897 ◽  
Author(s):  
Nan Chen ◽  
Zhenya Zhang ◽  
Chuanping Feng ◽  
Miao Li ◽  
Rongzhi Chen ◽  
...  

Kanuma mud, a geomaterial, is used as an adsorbent for the removal of fluoride from water. The influences of contact time, solution pH, adsorbent dosage, initial fluoride concentration and co-existing ions were investigated by batch equilibration studies. The rate of adsorption was rapid with equilibrium being attained after about 2 h, and the maximum removal of fluoride was obtained at pH 5.0–8.0. The Freundlich isotherm model was found to represent the measured adsorption data well. The negative value of the thermodynamic parameter ΔG suggests the adsorption of fluoride by Kanuma mud was spontaneous, the endothermic nature of adsorption was confirmed by the positive ΔH value. The negative ΔS value for adsorbent denoted decreased randomness at the solid/liquid interface. The adsorption process using Kanuma mud followed the pseudo-second-order kinetic model. Fluoride uptake by the Kanuma mud was a complex process and intra-particle diffusion played a major role in the adsorption process. It was found that adsorbed fluoride could be easily desorbed by washing the adsorbent with a solution of pH 12. This indicates the material could be easily recycled.


Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4464
Author(s):  
Sidra Gran ◽  
Rukhsanda Aziz ◽  
Muhammad Tariq Rafiq ◽  
Maryam Abbasi ◽  
Abdul Qayyum ◽  
...  

This research aims to assess the efficiency of the synthesized corncob as a cost-effective and eco-friendly adsorbent for the removal of heavy metals. Therefore, to carry out the intended research project, initially, the corncob was doped with nanoparticles to increase its efficiency or adsorption capacity. The prepared adsorbent was evaluated for the adsorption of cadmium (Cd) and chromium (Cr) from aqueous media with the batch experiment method. Factors that affect the adsorption process are pH, initial concentration, contact time and adsorbent dose. The analysis of Cd and Cr was performed by using atomic absorption spectrometry (AAS), while the characterization of the adsorbent was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that there is a significant difference before and after corncob activation and doping with CeO2 nanoparticles. The maximum removal for both Cd and Cr was at a basic pH with a contact time of 60 min at 120 rpm, which is 95% for Cd and 88% for Cr, respectively. To analyze the experimental data, a pseudo-first-order kinetic model, pseudo-second-order kinetic model, and intra-particle diffusion model were used. The kinetic adsorption studies confirmed that the experimental data were best fitted with the pseudo-second-order kinetic model (R2 = 0.989) and intra-particle diffusion model (R2 = 0.979). This work demonstrates that the cerium oxide/corncob nanocomposite is an inexpensive and environmentally friendly adsorbent for the removal of Cd and Cr from wastewater.


2017 ◽  
Vol 49 (3) ◽  
pp. 235-246 ◽  
Author(s):  
Nina Obradovic ◽  
Suzana Filipovic ◽  
Jelena Rusmirovic ◽  
Georgeta Postole ◽  
Aleksandar Marinkovic ◽  
...  

In this paper, synthesis of porous wollastonite-based ceramics was reported. Ceramic precursor, methylhydrocyclosiloxane, together with micro-sized CaCO3, was used as starting material. After 20 min of ultrasound treatment, and calcination at 250 oC for 30 min, yeast as a pore-forming agent was added to the as-obtained powders. Sintering regime was set up based on the results obtained by differential thermal analysis. Prepared mixture was pressed into pallets and sintered at 900 oC for 1 h. After the sintering regime, porous wollastonite-based ceramics was obtained. The phase composition of the sintered samples as well as microstructures was analyzed by X-ray diffraction method and SEM. In a batch test, the influence of pH, contact time and initial ion concentration on adsorption efficiency of As+5, Cr+6, and phosphate ions on synthesized wollastonite-based ceramics were studied. Time-dependent adsorption was best described by pseudo-second-order kinetic model and Weber-Morris model that predicted intra-particle diffusion as a rate-controlling step of overall process. High adsorption capacities 39.97, 21.87, and 15.29 mgg-1 were obtained for As+5, Cr+6, and phosphate ions, respectively.


2017 ◽  
Vol 79 (6) ◽  
Author(s):  
Budi Hastuti ◽  
Dwi Siswanta ◽  
Mudasir Mudasir ◽  
Triyono Triyono

Pectin and chitosan are biomaterials that capable to act as biosorbent. Pectin has active groups, such as carboxyl, methoxyl, and hydroxyl (OH), while chitosan has amine group (–NH2) and hydroxyl (OH) as the active site metal ion absorber. Integration of two biopolymers is conducted by using a suitable cross-linker agents that are expected to form stable and more organized structure. This structure facilitate metal ions to enter and to form chelation reaction. Thus, it has great capacity for metal adsorption. A modified natural adsorbent pectin-chitosan has been synthesized by reacting of -OH group among pectin (Pec) and chitosan with Poly(ethylene glycol) Diglycidyl Ether (PEGDE) crosslinker agent to form a stable and an acidic medium-resistance adsorbent. Prior to increasing the active group of the adsorbent, chitosan was attached with acetate to form Carboxymethyl Chitosan (CMC). Furthermore, the CMC-Pec-PEGDE adsorbent was imprinted with Pb (II) to afford Pb(II) imprinted-CMC-Pec-PEGDE adsorbent in order to improve the selective sorption of Pb(II) metal ion. All of the functional groups attached on the synthesized adsorbents were characterized by Fourier Transform Infrared (FT-IR) Spectrometry. The kinetics and thermodynamics bath sorption of Pb(II) on Pb(II) imprinted-CMC-Pec-PEGDE film adsorbent have been investigated including the optimal condition for adsorption. The pseudo first-order and second-order kinetic model were investigated in order to determine the adsorption mechanism. The results indicated that all of the three adsorbent, CMC, CMC-Pec-PEGDE, and Pb(II) imprinted-CMC-Pec-PEGDE followed a pseudo-second-order kinetic model. Furthermore, adsorption studies of Pb(II) ion on CMC and CMC–Pec-PEGDE found to follow Langmuir adsorption while on imprinted-CMC-Pec-PEGDE followed Freundlich adsorption isotherm. The adsorption isotherm parameters of CMC and CMC-Pec-PEGDE adsorbents were ΔG° of 24.8 and 23.1 kJ mol-1, respectively. While Pb(II) imprinted-CMC-Pec-PEGDE followedisotherm model with ΔG° of 9.6 kJ mol-1.


2019 ◽  
Author(s):  
Chem Int

An easy route for preparation emulsion of kaolinite (Al2Si2O5.4H2O) from Sweileh sand deposits, west Amman, Jordan by hydrochloric acid under continuous stirring for 4 h at room temperature was performed and nano kaolinite powder was used as an adsorbent for the removal of Cu(II), Zn(II) and Ni(II) ions. Nano kaolinite was characterized by XRD, FT-IR and SEM techniques. Effect of pH, adsorbent dose, initial metal ion concentration, contact time and temperature on adsorption process was examined. The negative values of ΔGo and the positive value of ΔHo revealed that the adsorption process was spontaneous and endothermic. The Langmuir isotherm model fitted well to metal ions adsorption data and the adsorption capacity. The kinetic data provided the best correlation of the adsorption with pseudo-second order kinetic model. In view of promising efficiency, the nano kaolinite can be employed for heavy metal ions adsorption.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Muhammad Hamid Raza ◽  
Aqsa Sadiq ◽  
Umar Farooq ◽  
Makshoof Athar ◽  
Tajamal Hussain ◽  
...  

Batch scale studies for the adsorption potential of novel biosorbentPhragmites karka(Trin), in its natural and treated forms, were performed for removal of mercury ions from aqueous solution. The study was carried out at different parameters to obtain optimum conditions of pH, biosorbent dose, agitation speed, time of contact, temperature, and initial metal ion concentration. To analyze the suitability of the process and maximum amount of metal uptake, Dubinin-Radushkevich (D-R) model, Freundlich isotherm, and Langmuir isotherm were applied. The values ofqmaxfor natural and treated biosorbents were found at 1.79 and 2.27 mg/g, respectively. The optimum values of contact time and agitation speed were found at 50 min and 150 rpm for natural biosorbent whereas 40 min and 100 rpm for treated biosorbent, respectively. The optimum biosorption capacities were observed at pH 4 and temperature 313 K for both naturalP. karkaand treatedP. karka.RLvalues indicate that comparatively treatedP. karkawas more feasible for mercury adsorption compared to naturalP. karka. Both pseudo-first-order and pseudo-second-order kinetic models were applied and it was found that data fit best to the pseudo-second-order kinetic model. Thermodynamic studies indicate that adsorption process was spontaneous, feasible, and endothermic.


2011 ◽  
Vol 71-78 ◽  
pp. 2988-2991
Author(s):  
Yuan Hong Wang ◽  
Yun Yu ◽  
Rui Qun Liu ◽  
Wei Feng Liu

Present study deals with the evaluation of biosorptive removal of nickel byFlavobacterium sp.Experiments have been carried out to find the effect of various parameters such as initial pH, contact time and initial metal ion concentration. Adsorption equilibrium studies showed that Ni(II) adsorption data followed the Langmuir model, the maximum binding capacity of Ni(II) was 64.20 mg/g at pH 7.0. Kinetics of nickel biosorption by Flavobacterium sp.biomass is better described by pseudo second order kinetic model. The equilibrium isotherm data are very well represented by Langmuir isotherm equation, which confirmed the monolayer coverage of nickel onto Flavobacterium sp.biomass. It was also clearly observed that The present study indicated thatFlavobacterium sp.biomass may be used as an inexpensive and effective biosorbent for the removal of Ni(II) ions from environmental wastewater.


2015 ◽  
Vol 10 (3) ◽  
pp. 729-737
Author(s):  
Imed Ghiloufi

Partial carbonized nanoporous resin (PCNR-150), based on organic xerogel compounds, was prepared at 150 ºC by sol–gel method from pyrogallol and formaldehyde mixtures in water using perchloric acid as catalyst. The PCNR-150 was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy (FTIR) and nitrogen porosimetry. The metal uptake characteristics were explored using well-established and effective parameters including pH, contact time, initial metal ion concentration, and temperature. Optimum adsorptions of Co2+ and Ni2+, using PCNR-150 as adsorbent, were observed at pH 5 and 7, respectively. Langmuir model gave a better fit than the other models, and kinetic studies revealed that the adsorption is fast and its data are well fitted by the pseudo-second-order kinetic model and thermodynamic properties, i.e., ΔGo, ΔHo, and ΔSo, showed that adsorption of Co2+ and Ni2+ onto PCNR-150 was endothermic, spontaneous and feasible in the temperature range of 300–328 K.


2019 ◽  
Vol 9 (4-A) ◽  
pp. 409-414 ◽  
Author(s):  
S. Krishnaveni ◽  
V. Thirumurugan

Pollution is the main problem due to heavy metal discharges from industries .  In this study Ipomoea carnea  (Family:Convolvulaceae) is selected to remove the heavy metal chromium from aqueous chromium solution using biosorbent . The present work focuses to evaluate the effectiveness of low cost absorbent Ipomoea carnea  root powder. Various parameters like pH, biosorbent, dose, contact time and metal ion concentration are investigated using batch studies. A kinetic model study and isotherm model fitting study are studied using Langmuir and Freundlich isotherms. The Thermodyamic parameters ∆G, ∆H and ∆S are also seen. The results reveal that it follows pseudo first order kinetic model and also fit in the Langmuir and Freundlich isotherms. The results are very much encouraging. So, it can be used as low cost biosorbent in controlling the pollution. Keywords: Pollution, Heavy metal, chromium, Ipomoea carnea, Batch adsorption study, Kinetics Langmuir and Freundlich isotherms and Thermodynamic study.


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