Competitive Adsorption between Polyethylene Glycol and Acid Brilliant Red on Expanded Graphite

Expanded graphite (EG) adsorbent was prepared with graphite as raw materials, potassium permanganate as oxidant, and vitriol as intercalation compound. Polyethylene glycol (PEG) 10000 and Acid brilliant red 3B (ABR) with obvious difference in molecular weights were selected as organic adsorbates, and their adsorption and competitive adsorption thermodynamics and kinetics on EG were investigated. The results are: In both single component system and dual component system, the adsorption and competitive adsorption isotherm of PEG 10000 and ABR on EG are all type I. In dual component system, the existence of another component would decrease the single component adsorbance, which might be caused by the competitive adsorption of these adsorbates for the same adsorbing site on EG. Adsorption and competitive adsorption are spontaneous, and the increase of ionic strength, temperature and expanded volume of the adsorbent would cause the increase of adsorbance. No matter the single component system or the dual component system, the adsorption kinetics models can all be well described with pseudo second-order model. Adsorption rate increases with the increase of temperature. Physical adsorption is the main action between EG with these adsorbates.

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Adsorption Characteristics of Polyvinyl Alcohols in Solution on Expanded Graphite

E-Journal of Chemistry ◽

10.1155/2012/461386 ◽

2012 ◽

Vol 9 (1) ◽

pp. 240-252 ◽

Cited By ~ 5

Author(s):

Xiu-Yan Pang

Keyword(s):

Raw Materials ◽

Physical Adsorption ◽

Intercalation Compound ◽

Expanded Graphite ◽

Kinetic Studies ◽

Degree Of Polymerization ◽

Second Order ◽

Order Kinetic ◽

Major Mode ◽

Initial Adsorption

Expanded graphite (EG) adsorbent was prepared with 50 mesh graphite as raw materials, potassium permanganate as oxidant, and vitriol as intercalation compound. Three kinds of polyvinyl alcohol (PVA) with different degree of polymerization (DP) in aqueous solution were used as adsorbates. We have studied the influence of initial PVA concentration, temperature and ionic strength on adsorption capacity. Langmuir constants and Gibbs free energy change (⊿G°) were calculated according to experimental data respectively. Thermodynamic analysis indicates the equilibrium adsorbance of PVA on EG increase with the rise of SO42–concentration. Adsorption isotherms of PVA with different degree of polymerization are all types and we deduce PVA molecules lie flat on EG surface. Adsorption processes are all spontaneous. Kinetic studies show that the kinetic data can be described by pseudo second-order kinetic model. Second-order rate constants and the initial adsorption rate rise with the increasing of temperature and half-adsorption time decreases with the increasing of temperature. The adsorption activation energy of each PVA is less than 20 kJ•mol−1, physical adsorption is the major mode of the overall adsorption process.

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Efficient Photocatalytic Hydrogen Production in a Single-Component System Using Ru,Rh,Ru Supramolecules Containing 4,7-Diphenyl-1,10-Phenanthroline

Angewandte Chemie ◽

10.1002/ange.201105170 ◽

2011 ◽

Vol 123 (51) ◽

pp. 12417-12421 ◽

Cited By ~ 17

Author(s):

Travis A. White ◽

Samantha L. H. Higgins ◽

Shamindri M. Arachchige ◽

Karen J. Brewer

Keyword(s):

Hydrogen Production ◽

Single Component ◽

Component System ◽

Photocatalytic Hydrogen Production ◽

Single Component System

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A New Analytic Method of Multistate Single-component System Reliability Model

MATEC Web of Conferences ◽

10.1051/matecconf/201817503058 ◽

2018 ◽

Vol 175 ◽

pp. 03058

Author(s):

Xie Jingwei ◽

Huang Peng ◽

Liu Gang

Keyword(s):

System Reliability ◽

Preventive Maintenance ◽

Single Component ◽

Matrix Analysis ◽

Phase Type Distribution ◽

Numerical Application ◽

Reliability Modeling ◽

Component System ◽

Mean Time Between Failures ◽

Single Component System

For the reliability modeling of multistate single-component system, single maintenance bench provides the preventive maintenance and alternative maintenance services on the basis of system performance level following the stochastic detection strategy. Phase-type distribution is employed in place of exponential distribution and other typical distributions to describe the stochastic time variable in the reliability modeling process in a unified manner. Through matrix analysis, the analytic expressions for reliability indicators including system steady-state availability, mean time between failures (MTBF) and failure rate of system are obtained. A numerical application is presented to verify the applicability of the model and demonstrate the influence of preventive maintenance threshold and preventive maintenance rate on system reliability.

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