scholarly journals Adsorption Behaviors of 17α-Ethinylestradiol in Sediment-Water System in Northern Taihu Lake, China

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Yonghua Wang ◽  
Liangfeng Hu ◽  
Qiuying Wang ◽  
Guanghua Lu ◽  
Yi Li
Keyword(s):  
Adsorption Capacity ◽  
Taihu Lake ◽  
Ph Value ◽  
Water System ◽  
Freundlich Isotherm ◽  
Hydroxyl Group ◽  
High Concentration ◽  
Competitive Effects ◽  
Adsorption Sites ◽  
Ph Values

Adsorption behavior of 17α-ethinylestradiol (EE2) in northern Taihu Lake sediment was analyzed by using batch equilibrium experiment. Freundlich isotherm could describe the adsorption thermodynamic behavior of EE2 in sediment. Sediment organic matter (SOM) contents had important impacts on the adsorption capacity for EE2. The pH values also influenced the adsorption capacity for EE2. Increase of pH value could decrease the EE2 adsorption, which might be due to the electrostatic repulsion between the anionic form of EE2 and sediments with negative charge under high pH values. Competitive effects of bisphenol A (BPA) on EE2 adsorption were further analyzed. The results showed that low concentration BPA did not have significant influences on EE2 adsorption. However, high concentration BPA could reduce EE2 adsorption, which might be due to the similar molecular diameter of BPA with adsorption sites and one more benzene ring with a hydroxyl group in BPA. These results provide primary information of EE2 adsorption in sediment-water system in Taihu Lake, which is useful for the environmental risk assessment and management of EE2 in studied area.

Adsorption of Organic Compounds on Refined Latvian Clay

2018 ◽  
Vol 788 ◽  
pp. 83-88
Author(s):  
Oskars Leščinskis ◽  
Ruta Švinka ◽  
Visvaldis Švinka
Keyword(s):  
Methyl Orange ◽  
Zeta Potential ◽  
Adsorption Capacity ◽  
Clay Minerals ◽  
Organic Compounds ◽  
Clay Mineral ◽  
Rhodamine B ◽  
Ph Value ◽  
Ftir Spectra ◽  
Ph Values

Clays are materials consisting of clay minerals and non-clay minerals. Clay mineral fraction is considered to be a nanofraction. Clay minerals can be used for water purification and treatment. Description and characterization of 3 different Latvian clay nanosized minerals from 3 different geological periods (clay Liepa from Devonian period, clay Vadakste from Triassic period and clay Apriki from Quaternary period) as well as their adsorption capacity concerning organic compounds such as methyl orange and rhodamine B are summarized. Nanosized clay mineral particles were obtained using sedimentation method. Particle size distribution, zeta potential and FTIR spectra is given. The adsorption tests of above mentioned organic compounds were carried out in water solutions at 3 different pH values. The adsorption values were determined by means of UV-spectrophotometric technique. Zeta potential values for clay minerals Apriki, Liepa and Vadakste are -40.9 mV, -49.6 mV and -43.0 mV, respectively. FTIR spectra show similar tendencies for all 3 clay minerals. The best adsorption capacity concerning methyl orange and rhodamine B were in solutions with a pH value of 2, whereas at neutral and alkaline pH values adsorption in 24 hours was not observed.

scholarly journals Sythesis of Nano Zerovalent Iron Supported Sawdust (NZVI/SD) and Its Application for Removal of Arsenic (III) from Aqueous Solution

2020 ◽  
pp. 1-12
Author(s):  
Tasrina R. Choudhury ◽  
Snahasish Bhowmik ◽  
M. S. Rahman ◽  
Mithun R. Nath ◽  
F. N. Jahan ◽  
...  
Keyword(s):  
Ph Value ◽  
Ferrous Sulphate ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Zerovalent Iron ◽  
Isotherm Model ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Adsorption Data ◽  
Pseudo Second Order

Sawdust supported nano-zerovalent (NZVI/SD) iron was synthesized by treating sawdust with ferrous sulphate followed by reduction with NaBH4. The NZVI/SD was characterized by SEM, XRD, FTIR and Chemical method. Adsorption of As (III) by NZVI/SD was investigated and the maximum uptake of As (III) was found at pH value of 7.74 and equilibrium time of 3 hrs. The adsorption isotherm modelling revealed that the equilibrium adsorption data were better fitted with the Langmuir isotherm model compared with the Freundlich Isotherm model. This study revealed that the maximum As (III) ions adsorption capacity was found to be 12.66 mg/g for using NZVI/SD adsorbent. However, the kinetics data were tested by pseudo-first-order and pseudo-second-order kinetic models; and it was observed that the adsorption data could be well fitted with pseudo-second-order kinetics for As (III) adsorption onto NZVI/SD depending on both adsorbate concentration and adsorption sites. The result of this study suggested that NZVI/SD could be developed as a prominent environment-friendly adsorbent for the removal of As (III) ions from aqueous systems.

Scalable Sulfonate-Coated Cotton Fibers as Facile Recyclable and Biodegradable Adsorbents for Highly Efficient Removal of Cationic Dyes

2021 ◽  
Author(s):  
Linhua Li ◽  
Baojie Dou ◽  
Jianwu Lan ◽  
Jiaojiao Shang ◽  
Yafang Wang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Large Scale ◽  
Ph Value ◽  
Cationic Dyes ◽  
Cotton Fibers ◽  
Wastewater Remediation ◽  
Efficient Removal ◽  
Adsorption Sites ◽  
Highly Efficient ◽  
Coated Cotton

Abstract Adsorbents with superior adsorption capacity and facile recyclability are viewed as promising materials for dye wastewater treatment. In this work, a novel sulfonate decorated cotton fiber as a biodegradable and recyclable adsorbent was fabricated for highly efficient removal of cationic dyes. Herein, the poly(sodium p-styrenesulfonate-co-N-methylol acrylamide) (P(SSNa-co-NMAM)) with SSNa units as adsorption sites and NMAM units as thermal-crosslinking points was synthesized for modification of cotton fibers in a large scale at high temperature (160 oC). The various characterization investigations confirmed the successful construction of the P(SSNa-co-NMAM) coated cotton fibers (PCF). As expected, the as-obtained adsorbent presented outstanding adsorption performance toward cationic dyes in the both static and dynamic states, even in the synthetic effluent. The adsorption processes of cationic dyes onto the PCF were well fitted by the Langmuir isotherm model and Pseudo-second-order kinetics, respectively. The thermodynamics study showed that the adsorption reaction of the cationic dyes onto PCF was a spontaneous and endothermic process. The maximum adsorption capacities of PCF toward MEB, RhB and MG were 3976.10, 2879.80 and 3071.55 mg/g, respectively. The responsible adsorption of dyes ontothe PCF was electrostatic interaction. Moreover, the adsorption capacity of PCF toward cationic dyes was slight influenced by pH value of solution, because of the stable feature of sulfonate moiety in acid and alkali. In addition, the as-prepared PCF exhibited satisfactory recyclability and reusability. Given the aforementioned results, the as-obtained PCF is a promising adsorbent with great potential for practical application in the dye-contaminated wastewater remediation.

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

scholarly journals β-Cyclodextrin Modified Poly(Acrylonitrule-co-Acrylic Acid) Hydrogel for Thorium(IV) Adsorption

Polymers ◽  
2017 ◽  
Vol 9 (6) ◽  
pp. 201 ◽  
Author(s):  
Guojian Duan ◽  
Qiangqiang Zhong ◽  
Lei Bi ◽  
Liu Yang ◽  
Tonghuan Liu ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Contact Time ◽  
Ph Value ◽  
Water System ◽  
Maximum Adsorption Capacity ◽  
Practical Application ◽  
X Ray Diffraction ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

In this report, the β-CD(AN-co-AA) hydrogel was used to remove the thorium(IV) [Th(IV)] from the water system, and the new adsorbent was characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The influences of contact time, pH value, ionic strength, solid-liquid ratio, initial Th(IV) concentration, and temperature on Th(IV) adsorption onto the functional hydrogel were researched. The results showed that the experimental data followed the Langmuir isotherm and the maximum adsorption capacity (qmax) for Th(IV) was 692 mg/g at pH 2.95, which approached the calculated (qe) 682 mg/g. The desorption capacity of Th(IV) in different HNO3 concentrations ranging from 0.005 to 0.5 M was also studied, and the percentage of the maximum desorption was 86.85% in the condition of 0.09 M HNO3. The selectivity of β-CD(AN-co-AA) hydrogel was also be studied, the results indicated that this material retained the good adsorption capacity to Th(IV) even when the Ca2+, Mg2+, or Pb2+ existed in the system. The findings indicate that β-CD(AN-co-AA) can be used as a new candidate for the enrichment and separation of Th(IV), or its analogue actinides, from large-volume solution in practical application.

scholarly journals Efficient Separation of Heavy Metals by Magnetic Nanostructured Beads

Inorganics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 40 ◽  
Author(s):  
Lisandra de Castro Alves ◽  
Susana Yáñez-Vilar ◽  
Yolanda Piñeiro-Redondo ◽  
José Rivas
Keyword(s):  
Heavy Metals ◽  
Ternary System ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Metal System ◽  
Adsorption Sites ◽  
Removal Of Heavy Metals ◽  
Adsorption Desorption ◽  
Efficient Adsorbent

This study reports the ability of magnetic alginate activated carbon (MAAC) beads to remove Cd(II), Hg(II), and Ni(II) from water in a mono-metal and ternary system. The adsorption capacity of the MAAC beads was highest in the mono-metal system. The removal efficiency of such metal ions falls in the range of 20–80% and it followed the order Cd(II) > Ni(II) > Hg(II). The model that best fitted in the ternary system was the Freundlich isotherm, while in the mono-system it was the Langmuir isotherm. The maximum Cd(II), Hg(II), and Ni(II) adsorption capacities calculated from the Freundlich isotherm in the mono-metal system were 7.09, 5.08, and 4.82 (mg/g) (mg/L)1/n, respectively. Lower adsorption capacity was observed in the ternary system due to the competition of metal ions for available adsorption sites. Desorption and reusability experiments demonstrated the MAAC beads could be used for at least five consecutive adsorption/desorption cycles. These findings suggest the practical use of the MAAC beads as efficient adsorbent for the removal of heavy metals from wastewater.

Adsorption of chromium (VI) from aqueous solutions on activated carbon

1994 ◽  
Vol 30 (9) ◽  
pp. 191-197 ◽  
Author(s):  
R. Leyva Ramos ◽  
A. Juarez Martinez ◽  
R. M. Guerrero Coronado
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Ph Effect ◽  
Freundlich Isotherm ◽  
Maximum Adsorption Capacity ◽  
Experimental Adsorption ◽  
Ph Values ◽  
Chromium Vi ◽  
Adsorption Data

The adsorption isotherm of chromium (VI) on activated carbon was obtained in a batch adsorber. The experimental adsorption data were fitted reasonably well to the Freundlich isotherm. The effect of pH on the adsorption isotherm was investigated at pH values of 4, 6, 7, 8, 10 and 12. It was found that at pH &lt; 6, Cr(VI) was adsorbed and reduced to Cr(III) by the catalytic action of the carbon and that at pH ≥ 12, Cr(VI) was not adsorbed on activated carbon. Maximum adsorption capacity was observed at pH 6 and the adsorption capacity was diminished about 17 times by increasing the pH from 6 to 10. The pH effect was attributed to the different complexes that Cr(VI) can form in aqueous solution. The adsorption isotherm was also affected by the temperature since the adsorption capacity was increased by raising the temperature from 25 to 40°C. It was concluded that Cr(VI) was adsorbed significantly on activated carbon at pH 6 and that the adsorption capacity was greatly dependent upon pH.

scholarly journals Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Juanjuan Liu ◽  
Xiaolong Wu ◽  
Yandi Hu ◽  
Chong Dai ◽  
Qin Peng ◽  
...  
Keyword(s):  
Distribution Coefficient ◽  
Adsorption Capacity ◽  
Removal Efficiency ◽  
Saturation Index ◽  
Surface Complexation ◽  
Maximum Adsorption Capacity ◽  
Positive Correlation ◽  
Adsorption Sites ◽  
Ph Values ◽  
Adsorption Behaviors

The adsorption of Cr(III) or Cr(VI) in the absence and presence of Cu(II) onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential(ζ), especially the hydrolysis behavior and saturation index of heavy metal ions. In the presence of Cu(II),qmixCr(III)reached the maximum adsorption capacity of 0.73 mg·g−1at pH 6.0, while the maximum adsorption capacity for the mixed Cr(VI) and Cu(II) system (qmixCr(VI)) was observed at pH 2.0 (0.38 mg·g−1). Comparing the adsorption behaviors and mechanisms, we found that kaolin prefers to adsorb hydrolyzed products of Cr(III) instead of Cr3+ion, while adsorption sites of kaolin surface were occupied primarily by Cu(II) through surface complexation, leading to Cu(II) inhibited Cr(VI) adsorption. Moreover, Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficientKd. Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficientKdand that of adsorption affinities of Cr(III) or Cr(VI) on kaolin was found to beKdCr(III) <KdCr(III)-Cu(II) andKdCr(VI) >KdCr(VI)-Cu(II).

ZnO submicron structures of controlled morphology synthesized in zinc-hexamethylenetetramine-ethylenediamine aqueous system

2007 ◽  
Vol 22 (7) ◽  
pp. 1815-1823 ◽  
Author(s):  
Xiang-Dong Gao ◽  
Xiao-Min Li ◽  
Sam Zhang ◽  
Wei-Dong Yu ◽  
Ji-Jun Qiu
Keyword(s):  
Reaction Temperature ◽  
Ph Value ◽  
Background Electrolyte ◽  
Aqueous System ◽  
Precursor Concentration ◽  
Submicron Particles ◽  
Hydroxyl Group ◽  
High Concentration ◽  
Inorganic Species ◽  
Flowerlike Structure

The morphology of ZnO submicron crystals formed in a weak alkaline environment (pH value less than 11.0) was systematically studied for the first time. ZnO submicron particles with different morphologies (flowers, rod, and wire) were synthesized from an aqueous solution by adopting ethylenediamine as the source of hydroxyl group, hexamethylenetetramine (HMT) as the additive, and potassium chloride (KCl) as the background electrolyte. The effects of primary experimental parameters such as HMT and KCl addition, precursor concentration, and reaction temperature on the microstructure, crystallinity of the resultant particles, and their distribution on substrate are discussed in this paper. In the flowerlike structure, the particle size is more controlled by the precursor concentration, and the microstructure is modulated by increasing the concentration of HMT and the reaction temperature. The introduction of ZnO seed layer on substrate promotes even distribution of ZnO flowers. High concentration KCl electrolyte inhibits formation of the flowerlike structure and promotes the growth of submicron ZnO crystals in rod or wire shape. Mechanism studies indicate that the degree of supersaturation of Zn(OH)2 and the adsorption of organic/inorganic species on the surface of ZnO are the prime factors influencing the nucleation, growth rate, and eventual morphology.

Adsorption of cadmium(II) from aqueous solution onto activated carbon

1997 ◽  
Vol 35 (7) ◽  
pp. 205-211 ◽  
Author(s):  
R. Leyva-Ramos ◽  
J. R. Rangel-Mendez ◽  
J. Mendoza-Barron ◽  
L. Fuentes-Rubio ◽  
R. M. Guerrero-Coronado
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Carbon Surface ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Ph Values ◽  
Average Percent Deviation ◽  
Initial Ph

The adsorption isotherm of cadmium on activated carbon was measured in a batch adsorber. Effects of temperature and solution pH on the adsorption isotherm were investigated by determining the adsorption isotherm at temperatures of 10, 25, and 40°C and at initial pH values from 2 to 8. Langmuir isotherm better fitted the experimental data since the average percent deviation was lower than with the Freundlich isotherm It was noticed that the amount of Cd2+ adsorbed was reduced about 3 times by increasing the temperature from 10 to 40°C. It was found that Cd2+ was not adsorbed on activated carbon at pH of 2 or lower and that Cd2+ was precipitated out as Cd(OH)2 at pH values above 9. Maximum adsorption capacity was observed at pH of 8 and the adsorption capacity was decreased about 12 times by reducing the initial pH from 8 to 3. According to the cadmium speciation diagram the predominant species below pH of 8 is Cd2+. Thus, cadmium was adsorbed on the activated carbon surface as Cd2+. It was concluded that the adsorption capacity is a strong function of pH and temperature.

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