scholarly journals Biosorption of Cr(VI) from AqueousSolution Using New Adsorbent: Equilibrium and Thermodynamic Study

2010 ◽  
Vol 7 (s1) ◽  
pp. S488-S494 ◽  
Author(s):  
Israa G. Zainal
Keyword(s):  
Physical Adsorption ◽  
Thermodynamic Study ◽  
Polluted Water ◽  
Isotherm Models ◽  
Biosorption Process ◽  
Naturally Occurring ◽  
Adsorption Isotherm Models ◽  
Optimum Ph ◽  
Solid Liquid Interface ◽  
Solid Liquid

Biosorption is one such emerging technology which utilized naturally occurring waste materials to sequester heavy metals from polluted water. In the present study cinnamon was utilized for Cr(VI) removal from aqueous solutions.It was found that a time of two hours was sufficient for sorption to attain equilibrium. The optimum pH was 2 for Cr(VI) removal. Temprature has little influence on the biosorption process. The Cr(VI) removal decreased with increase in temperature. The biosorption data was well fitted to Dubinin - Radushkevich (D-R), Freundlich and Tempkin adsorption isotherm models, although the correlation coefficient of Langmuir model was high but the calculated adsorption capacity did not agree with the experimental. The thermodynamic study reveals that the biosorption process is spontaneous and the spontaneity decreased with temperature increase and the process is exothermic accompanied by highly ordered adsorbate at the solid liquid interface. ΔH°values were negative and lie in the range of physical adsorption.

scholarly journals Adsorptive Removal of Copper Ions from Polluted Water Using Sorbents Derived from Cordia dichotoma, Albizia thompsonii and Polyalthia cerasoides Plants

2020 ◽  
Vol 32 (10) ◽  
pp. 2653-2659
Author(s):  
Tumma Prasanna Kumar Reddy ◽  
Sayana Veerababu ◽  
Malireddy Venkata Sai Mohan Reddy ◽  
Kunta Ravindhranath
Keyword(s):  
Activated Carbons ◽  
Copper Ions ◽  
Industrial Effluent ◽  
Industrial Effluents ◽  
Liquid Interface ◽  
Polluted Water ◽  
Physico Chemical ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Direct Applicability

Three different activated carbons as effective adsorbents were prepared by digesting the stems of Cordia dichotoma, Albizia thompsonii and Polyalthia cerasoides plants in conc. H2SO4 for Cu2+ removal from wastewater. The sorption natures of these sorbents are optimized with respect to various physico-chemical characteristics for the maximum Cu2+ removal using simulated waters. Cordia dichotoma (CDAC), Albizia thompsonii (ATAC) and Polyalthia cerasoides (PCAC) activated carbons show good sorption capacities of values: 97.0, 76.8 and 66.7 mg/g, respectively in a wide pH ranges. Unlike that of other two activated carbons, Cordia dichotoma activated carbon is effective even in acid conditions, indicting its direct applicability to Cu-based industrial effluents which are generally acidic in nature. Interference of two fold excess of co-ions is minimal. The established extraction conditions for the removal of more than 95.0% from 10 ppm Cu2+ solution at room temperature (303 K) using CDAC as sorbent are: pH: 3-9; time of equilibration: 1 h; sorbent dosage: 0.100 g/100 mL; with ATAC: pH: 6-9; time of equilibration: 1.5 h and sorbent dosage: 0.125 g/100 mL; and with PCAC: pH: 6-9; time of equilibration: 2.0 h and sorbent dosage 0.50 g/100 mL. Spent adsorbents can be regenerated and reused until four cycles with minimal loss of adoption capacities. Thermodynamic studies revealed that the sorption is spontaneous and endothermic in nature. Further, the ΔH value for CDAC is 30.156 KJ/mol; it indicates the strong chemisorption and may be through reduction to Cu+/Cu and/or complex formation between Cu2+ and functional groups of the adsorbent. The ΔH values of other two activated carbons, ATAC and PCAC, indicated that the sorption is mainly physical with strong inclination towards chemical nature. Positive ΔS values of all the three sorbents, emphasizes the disorder or randomness at the solid-liquid interface and hence favourable conditions for more penetration of Cu2+ into the surface layers of the adsorbent and hence, more removal of Cu2+ ions. The negative ΔG values indicate that the sorption forces are good enough to cross the potential barrier at the solid-liquid interface and hence the process is spontaneous. The prepared three activated carbons were also successfully applied to industrial effluent and polluted lake samples.

scholarly journals OPTIMIZATION AND SORPTION ISOTHERMS ANALYSIS OF ANIONIC DYE EOSIN YELLOW DECONTAMINATION BY GOETHITE ADSORBENTS

2020 ◽  
Vol 4 (2) ◽  
pp. 75-81
Author(s):  
Nasir Abdus- Salam ◽  
Fabian Audu Ugbe ◽  
Abiola Victoria Ikudayisi- Ugbe
Keyword(s):  
Particle Size ◽  
Physical Adsorption ◽  
Sorption Isotherms ◽  
Isotherm Models ◽  
Sorption Data ◽  
Isotherm Study ◽  
Monolayer Adsorption ◽  
Adsorption Isotherm Models ◽  
Adsorption Processes ◽  
Eosin Yellow

In this work, removal of Eosin Yellow (EY) using Natural Goethite (NGT) and Synthetic Goethite (SGT) particles was studied using batch equilibrium technique. Different parameters such as initial dye concentration, particle size (NGT only), pH, and adsorbent dose were optimized to investigate the sorbents efficiency for the dye. The experimental data were tested for fitness into five common adsorption isotherm models. The various equilibrium parameters studied were found to have remarkable influence on the adsorption processes, showing optimum removal at dye concentration (150 mg/L for EY-NGT and 200 mg/L for EY-SGT), NGT particle size (0.112mm), pH (2), and dosage (0.05g), with SGT exhibiting relatively higher adsorption efficiency. The sorption data fitted well the various isotherm models in the order; Freundlich (R2 = 0.9032) > Temkin (0.8294) > Langmuir (0.8268) > DKR (0.6431) > Flory Huggins (0.616) for EY-NGT, and Langmuir (0.9831) > Flory Huggins (0.9639) > Freundlich (0.9597) > Temkin (0.8944) > DKR (0.5993) for EY-SGT. The monolayer adsorption capacity (qm) was calculated as 1.17 and 20.80 mgg-1 for NGT and SGT respectively. Additionally, combined information obtained from the isotherm study revealed that the processes were favourable, spontaneous and proceeded by a multilayer physical adsorption on already chemisorbed layer. Conclusively, the results of this study have provided useful information on the optimum working condition and mechanism of EY uptake onto goethite surfaces.

Equilibrium and Thermodynamic Studies on Biosorption of Dye from Aqueous Solution by PeniciIlium sp.

2011 ◽  
Vol 80-81 ◽  
pp. 678-682
Author(s):  
Li Fang Zhang ◽  
Ying Ying Chen ◽  
Shu Juan Dai
Keyword(s):  
Aqueous Solution ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Freundlich Model ◽  
Thermodynamic Studies ◽  
Biosorption Process ◽  
Optimum Ph ◽  
Initial Ph ◽  
Equilibrium Data ◽  
Increasing Temperature

In this study, biosorption of C. I. Acid Red 18 from aqueous solution was investigated by using acid treated biomass of Penicilium sp. in a batch system. The effects of initial pH, contact time, initial dye concentration and temperature on dye biosorption were investigated. Optimum pH for efficient dye biosorption was found to be 3.0 for acid treated biomass. The bosorption capacity was increased with the increasing temperature in studied temperature range. The Langmuir and Freundlich isotherm models were applied to experimental equilibrium data and the Langmuir model better described the equilibrium dye uptake than the Freundlich model. Thermodynamic studies revealed that the biosorption process was successful, spontaneous and endothermic in nature.

Biogenic Jarosite: A Friendly Adsorbent for the Removal of Chromate from Aqueous Solution

2015 ◽  
Vol 737 ◽  
pp. 533-536 ◽  
Author(s):  
Dong Xue Xiao ◽  
Chang Ling Fang ◽  
Jun Zhou ◽  
Xiao Yi Lou ◽  
Jiu Hua Xiao ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Isotherm ◽  
Mine Drainage ◽  
Langmuir Adsorption Isotherm ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Langmuir Adsorption ◽  
Adsorption Isotherm Models ◽  
Optimum Ph ◽  
Sulfate Leaching

Ferric hydrosulfate minerals are commonly byproducts of biotic oxidation of Fe (II) in acid mine drainage and biohydrometallurgy like biogenic jarosite. In this study, adsorption of Cr (VI) on jarosite was a rapid process and the optimum pH for Cr (VI) adsorption was found at 7.0. The variation of Cr (VI) adsorbed on jarosite fitted the Langmuir adsorption isotherm models and the maximum adsorption capacity was 3.23 mg/g. It was evident that anion exchange mechanism was responsible for Cr (VI) adsorption on jarosite based on the sulfate leaching data and optimum pH experiments.

Adsorptive removal of As(III) from aqueous solution by waste litchi pericarps

2016 ◽  
Vol 74 (9) ◽  
pp. 2135-2144 ◽  
Author(s):  
Xiaochen Li ◽  
Jinqiu Qi ◽  
Ruixue Jiang ◽  
Jie Li
Keyword(s):  
Contact Time ◽  
Influential Factors ◽  
Isotherm Models ◽  
Solution Ph ◽  
Rate Limiting Step ◽  
Pseudo Second Order ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Rate Limiting ◽  
Adsorbent Dose

The present study investigated the removal of arsenite anions (AsO33−, referred to as As(III)) from aqueous solutions by waste litchi pericarps (LPs). Influential factors such as the adsorbent dose, contact time, solution pH, and initial As(III) concentration were investigated. The optimum conditions for As(III) adsorption by the LPs occurred at a contact time of 60 min, adsorbent dose of 10.0 g/L, solution pH of 5.0, and initial As(III) concentration of 1 mg/L. A Box–Behnken design with three variables (adsorbent dose, contact time, and solution pH) at three different levels was studied to identify the correlations between the influential factors and the As(III) adsorption; the results showed a significant interaction between the adsorbent dosage and pH. Additionally, adsorption isotherms, kinetics, and thermodynamics were investigated to explore the As(III) adsorption mechanism. Adsorption by the LPs conformed to the Langmuir, Redlich–Peterson, and Koble–Corrigan isotherm models, suggesting that the process proceeds via monolayer, homogeneous adsorption. In addition, the As(III) adsorption could be characterized by a pseudo-second-order mechanism, revealing that the rate-limiting step might be chemisorption. The thermodynamic studies showed that As(III) adsorption by the LPs was spontaneous and endothermic, and disorder at the solid–liquid interface increased in the adsorption process.

Atom-probe analysis of the solid-liquid interface

1995 ◽  
Vol 53 ◽  
pp. 676-677
Author(s):  
J.A. Panitz
Keyword(s):  
Molecular Level ◽  
Selective Adsorption ◽  
Electronic Devices ◽  
Atom Probe ◽  
Chemical Agent ◽  
Hostile Environment ◽  
Solid Interface ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Chemically Selective

The first few atomic layers of a solid can form a barrier between its interior and an often hostile environment. Although adsorption at the vacuum-solid interface has been studied in great detail, little is known about adsorption at the liquid-solid interface. Adsorption at a liquid-solid interface is of intrinsic interest, and is of technological importance because it provides a way to coat a surface with monolayer or multilayer structures. A pinhole free monolayer (with a reasonable dielectric constant) could lead to the development of nanoscale capacitors with unique characteristics and lithographic resists that surpass the resolution of their conventional counterparts. Chemically selective adsorption is of particular interest because it can be used to passivate a surface from external modification or change the wear and the lubrication properties of a surface to reflect new and useful properties. Immunochemical adsorption could be used to fabricate novel molecular electronic devices or to construct small, “smart”, unobtrusive sensors with the potential to detect a wide variety of preselected species at the molecular level. These might include a particular carcinogen in the environment, a specific type of explosive, a chemical agent, a virus, or even a tumor in the human body.

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