Branched-pore model applied to the adsorption of basic dyes on carbon

The branched-pore adsorption model, expressed by an external mass transfer coefficient k_f, a solid diffusivity D_s, a lumped micropore diffusion rate parameter k_b, and the fraction of macropores f, describes kinetic data from initial contact of adsorbent-adsorbate to the long-term ( > 24 hours) adsorption stages with reasonable accuracy.In this work the model is applied for three basic dye systems, namely Basic Red 22, Basic Yellow 21 and Basic Blue 69, all on carbon. A single value of each parameter describes each dye system. The k_f values are 0.18 × 10⁻²±28%, 0.3 × 10⁻²±17% and 0.2 × 10⁻² ± 20% cm s⁻¹, the D_s values are 0.33 × 10⁻⁹ 21%, 0.72 × 10⁻⁹ ± 9% and 0.72 × 10⁻⁹ ± 9% cm² s⁻¹, the k_b values are 0.65 × 10⁻⁶ ± 7.7%, 1.8 × 10⁻⁶ 0.2 × 10⁻⁶ 1% s⁻¹, while the f values are 0.55 ± 9%, 0.60 ± 10 % and 0.18 ± 11%, each for Basic Red 22, Basic Yellow 21 and Basic Blue 69 respectively.The model is based on the internal structure of the carbon particle being divided into a macropore and a micropore region. The latter has an upper-bound capacity of 241, 245 and 656 mg g⁻¹ for Basic Red 22, Basic Yellow 21 and Basic Blue 69 respectively. A sensitivity analysis for each parameter has been carried out.     

Control of ferroelectric and linear piezoelectric response of PZT films through texture

The high and low field ferroelectric response of freestanding PbZr_0.52Ti_0.48O₃ (PZT) films, with texture varying from 100% (001) to 100% (111) was investigated via 500 nm thick PZT unimorphs deposited on the same substrate. It is shown that the ferroelectric and piezoelectric properties depend strongly on texture, and the effective transverse strain and stress coefficients vary linearly with %(001) and %(111) texture factors. PZT films with 100% (001) orientation displayed 150%, 140%, and 80% larger linear piezoelectric strain coefficient, saturated strain coefficient, and saturated stress coefficient, respectively, compared to films with 100% (111) orientation. As a result, pure (001) textured PZT films with 20% higher dielectric constant have 50% higher figure of merit in sensing than films with pure (111) texture. The piezoelectric and ferroelectric properties of all but one combinations of (001) and (111) texture were shown for the first time to be bounded by the values for 100% (001) and 100% (111) texture. A notable exception was PZT films comprised of 73% (001) and 27% (111) texture which showed stable piezoelectric coefficients at all electric fields, with major technological implication to low power microdevices. Finally, the coercive field was shown to decrease with (001) texture factor and excess‐Pb in the PZT and the PbTiO₃ seed layer.     

Deterioration Kinetics of Crude Palm Oil,Canola Oil and Blend During Repeated Deep-Fat Frying

The oxidation of vegetable oils is generally treated as an apparent first order kinetic reaction. This study investigated the deterioration of crude palm oil (CPO), refined canola oil (RCO) and their blend (CPO:RCO 1:1 w/w) during 20 h of successive deep‐fat frying at 170, 180 and 190 °C. Kinetics of changes in oil quality indices, namely, free fatty acid (FFA), peroxide value (PV), anisidine value (p‐AV), total polar compounds (TPC) and color index (CI) were monitored. The results showed that FFA and PV accumulation followed the kinetic first order model, while p‐AV, TPC and CI followed the kinetic zero order model. The concentration and deterioration rate constants k, increased with increasing temperatures. This effect of temperature was modeled by the Arrhenius equation. The results showed that PV had the least activation energies E_a (kJ/mol) values of 5.4 ± 1 (RCO), 6.6 ± 0.7 (CPO) and 11.4 ± 1 (blend). The highest E_a requirement was exhibited by FFA with a range of 31.7 ± 3–76.5 ± 7 kJ/mol for the three oils. The overall E_a values showed that the stability of the blend was superior and not just intermediate of CPO and RCO. The correlation of the other oil quality indices with TPC indicated a positive linear correlation. The p‐AV displayed the strongest correlation, with mean correlation coefficient r_s of 0.998 ± 0.00, 0.994 ± 0.00 and 0.999 ± 0.00 for CPO, RCO and blend, respectively.     

Effect of the processing methods on the performance of polylactide films: Thermocompression versus solvent casting

Polylactide (PLA) films were prepared by the thermocompression and solvent‐casting methods, and selected properties, such as the mechanical, water‐vapor‐barrier, thermal, and thermomechanical properties, were tested. The solvent‐cast films contained 13.7% solvent, which functioned as a plasticizer, as evidenced by the results of the measurements of dry matter and thermogravimetric analysis as well as dynamic mechanical analysis. The PLA films prepared by the thermocompression method were strong and brittle, with maximum tensile strength (σ_max) and maximum elongation at break (?_max) values of 44.0 ± 2.2 MPa and 3.0 ± 0.1%, respectively; however, the solvent‐cast films were more ductile, with σ_max and ?_max values of 16.6 ± 1.0 MPa and 203.4 ± 20.8%, respectively. The water vapor permeability of the PLA films was lower than that of plastic films such as low‐density polyethylene and high‐density polyethylene but higher than that of commonly used biopolymer films. In addition, both types of tested PLA films were water‐resistant and not soluble in water. The thermocompressed films showed higher thermal stability than the solvent‐cast films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3736–3742, 2006     

Analysis of piezoresistive properties of CVD-diamond films on silicon

The piezoresistive properties of CVD-diamond are still very much in discussion since not only the materials energy band structure properties have to be considered but also the grain boundaries and internal stress distribution. Here, the experimental piezoresistive properties of CVD-diamond-on-silicon layers for free standing structures have been investigated comprehensively. The longitudinal gauge factor k_l has been extracted using freestanding diamond cantilevers on silicon. The piezoresistors have been grown selectively onto the surface of diamond cantilevers near the mechanical suspension and doped with boron (acceptor). The electrical contacts are based on the tunneling mechanism with a silicon-based multilayer metalization leading to a linear IV-characteristic. Gauge factor values, k_l, have been extracted on various structures with different doping concentrations and diamond film quality (highly oriented and textured, textured, randomly oriented), depending on temperature (room temperature, −350°C) and intrinsic stress. Highly oriented and textured films with grain sizes between 3 and 10 μm have been used to realize ‘single grain’ resistor structures enabling the investigation of grain boundaries in the electrical current path of the piezoresistor. Raman measurements have been performed to measure the intrinsic stress in the diamond grains. Gauge factors, k_l of between 4 and 28 have been extracted. Largest k_l values were observed on piezoresistors on highly oriented and textured diamond (HOD) films. Results of this work have been used in piezoresistive sensor applications.     

Heavy Metal Removal and Neutralization of Acid Mine Waste Water ‐ Kinetic Study

The influence of the apatite on the efficiency of neutralization and on heavy metal removal of acid mine waste water has been studied. The analysis of the treated waste water samples with apatite has shown an advanced purification, the concentration of the heavy metals after the treatment of the waste water with apatite being 25 to 1000 times less than the Maximum Concentration Limits admitted by European Norms (NTPA 001/2005). In order to establish the macro‐kinetic mechanism in the neutralization process, the activation energy, Ea, and the kinetic parameters, rate coefficient of reaction, k_r, and k_t were determined from the experimental results obtained in “ceramic ball‐mill” reactor. The obtained values of the activation energy Ea >> 42 kJ mol^?1 (e.g. Ea = 115.50 ± 7.50 kJ mol^?1 for a conversion of sulphuric acid η_H2SO4 = 0.05, Ea = 60.90 ± 9.50 kJ mol^?1 for η ^H2SO4 = 0.10 and Ea = 55.75 ± 10.45 kJ mol^‐1 for η ^H2SO4 = 0.15) suggest that up to a conversion of H2SO4 equal 0.15 the global process is controlled by the transformation process, adsorption followed by reaction, which means surface‐controlled reactions. At a conversion of sulphuric acid η ^H2SO4 > 0.15, the obtained values of activation energy Ea < 42 kJ mol^‐1 (e.g. Ea = 37.55 ± 4.05 kJ mol^‐1 for η ^H2SO4 = 0.2, Ea = 37.54 ± 2.54 kJ mol^‐1 for η ^H2SO4 = 0.3 and Ea = 37.44 ± 2.90 kJ mol^‐1 for η ^H2SO4 = 0.4) indicate diffusion‐controlled processes. This means a combined process model, which involves the transfer in the liquid phase followed by the chemical reaction at the surface of the solid. Kinetic parameters as rate coefficient of reaction, kr with values ranging from (5.02 ± 1.62) 10‐4 to (8.00 ± 1.55) 10‐4 (s^‐1) and transfer coefficient, kt, ranging from (8.40 ± 0.50) 10‐5 to (10.42 ± 0.65) 10‐5 (m s^‐1) were determined.     

Tribological behaviour of <100> and <111> fibre textured CVD diamond films under dry planar sliding contact

<100> and <111> fibre textured diamond films are grown on SSiC sliding rings by hot filament CVD and are tribologically tested in dry planar contact under ambient air.The wear of the self-mated textured diamond coating takes place initially at protruding grains of the as-deposited micro rough diamond surface. After 10 km of dry sliding against <100> textured diamond the respective counterparts with <100> and <111> textures exhibit smoothly polished diamond faces without visible surface failures. After dry sliding against <111> textured diamond as static counterpart {100} diamond faces of isolated grains show Hertzian cone cracks and propagation of cracks preferred along {111} easy cleavage planes whereas {111} diamond faces reveal no crack propagation in substrate direction.The results are visualised in a tribo map in which the linear wear of the dynamic diamond face is plotted against the mean coefficient of friction. The best tribological behaviour in terms of low friction and little diamond wear is achieved for sliding couples with <100> fibre texture on the rotating sliding ring and <111> fibre texture on the static ring as mating diamond faces.     

Reaction Kinetics of Hydroxyl Radicals with Model Compounds of Fuel Cell Polymer Membranes

The chemical stability of perfluorinated and non‐perfluorinated low temperature fuel cell model compounds (MCs) against attack by hydroxyl radicals, HO^•, is compared using a competition kinetics approach in aqueous solutions at ambient temperature. HO^• radicals were generated in situ by UV photolysis of hydrogen peroxide in the electron spin resonance (ESR) resonator. Acetic acid (AA), trifluoroacetic acid (TFAA), methanesulfonic acid (MSA), trifluorosulfonic acid (TFSA), and perfluoro(2‐ethoxyethane)sulfonic acid (PFEESA) were chosen as MCs, while the rate constants of 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO) and methanol (CH₃OH) served as reference for the determination of relative rate constants by means of steady state ESR signal amplitudes. In decreasing order the rate constants are: k_MSA = (4.8 ± 0.2) × 10⁷ M^–1 s^–1, k_AA = (4.2 ± 0.3) × 10⁷ M^–1 s^–1, k_PFEESA = (3.7 ± 0.1) × 10⁶ M^–1 s^–1, k_TFAA = (7.9 ± 0.2) × 10⁵ M^–1 s^–1, and k_TFSA < 1.0 × 10⁵ M^–1 s^–1. Applying these results to perfluorinated fuel cell membranes like Nafion®, the main points of attack by HO^• are concluded to be the ether groups of the side chains, followed by the remaining carboxyl groups from the manufacturing process of the polymers.     

Epoxy composite reinforced with three‐dimensional polyimide fiber felt: Fabrication and tribological properties investigation

Novel epoxy (EP) composite reinforced with three‐dimensional (3D) polyimide (PI) fiber felt (PI_3D/EP) is first fabricated by vacuum assisted resin transfer molding. The tribological behaviors of pure EP and PI_3D/EP composite under dry sliding and water lubricated condition are comparatively studied. Results indicate that both wear rates and friction coefficients of PI_3D/EP composite are lower than those of pure EP. The wear resistance of PI_3D/EP composite is 9.8 times higher than that of pure EP under dry sliding of 1.5 MPa and 0.76 m s^?1 while a 27‐fold increase is achieved under water lubricated condition. The wear mechanisms of PI_3D/EP composite are investigated based on tribological testing results and scanning electron microscopy observations. The PI fiber felt provides strong 3D structure supports to sustain most of the loads on the composite, improving the mechanical and tribological properties significantly. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44160.     

Investigation of texture effect on visual colour difference evaluation

The texture effect on visual colour difference evaluation was investigated in this study. Five colour centers were selected and textured colour pairs were generated using scanned textile woven fabrics and colour‐mapping technique. The textured and solid colour pairs were then displayed on a characterized cathode ray tube (CRT) monitor for colour difference evaluation. The colour difference values for the pairs with texture patterns are equal to 5.0 CIELAB units in lightness direction. The texture level was represented by the half‐width of histogram, which is called texture strength in this study. High correlation was found between texture strength and visual colour difference for textured colour pairs, which indicates that an increasing of 10 units of texture strength in luminance would cause a decreasing of 0.25 units visual difference for the five colour centers. The ratio of visual difference between textured and solid colour pairs also indicates a high parametric effect of texture. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 341–347, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.     

Study on the tribological properties of porous sweating PEEK composites under ionic liquid lubricated condition

The tribological behaviors of novel porous Polyetheretherketone (PEEK) composites under 1‐hexyl‐3‐methylimidazolium tetrafluoroborate ionic liquid lubricated condition were investigated. The effect of sliding velocity and applied load on the sweating tribological properties and the stability of lubricating oil film was also studied. Results indicated that when the sliding velocity was 0.69 m/s and the applied load was 250 N, the friction coefficient and wear rate of the ionic liquid lubricated porous sweating activated carbon fiber/polytetrafluoroethene/PEEK composites showed the minimum values, were 0.0197 and 4.145 × 10^?15 m³/Nm, respectively. The friction coefficients fluctuated in a narrow range of 0.0162–0.0215. It was found that the porous sweating PEEK composites under ionic liquid lubricated condition showed good low‐friction and antiwear performance, especially under the condition of high sliding velocity and applied load. The formed transfer film due to the tribo‐chemical reaction as well as boundary lubricating film is effective in improving the carrying capacity and antiwear properties of the porous sweating PEEK composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40989.     

Perpetual effect of laser surface texturing on tribological properties of Ti3SiC2/GNP composite—A fretting wear study

Tribological properties of Ti₃SiC₂ ceramic and Ti₃SiC₂/GNP composite were investigated using fretting sliding against Si₃N₄ ball counter body at a load of 50 N for a sliding distance of 900 m, under non-textured lubricated (NTL), textured lubricated (TL) condition, and textured lubricated high temperature (TLHT). This paper presents the influence of laser surface texturing (LST) on Ti₃SiC₂ and its graphene nanoplatelets (GNP) reinforced composite established through spark plasma sintering (SPS), tested under fretting wear conditions. The coefficient of friction and wear rate of Ti₃SiC₂ and its graphene nanoplatelets reinforced composites were incontrovertibly enhanced with laser surface texturing as compared to non-textured Ti₃SiC₂ and its GNP composite. The TL surface of Ti₃SiC₂ composite reinforced with 15% GNP showed the lowest COF and wear rate. Almost negligible changes were observed for TLHT tests. The LST proved to an efficient technique for enhancing the friction and wear properties of Ti₃SiC₂ and Ti₃SiC₂/GNP composite.     

Open hole flexural and izod impact strength of unidirectional flax yarn reinforced polypropylene composites as a function of laminate lay‐up

An open hole flexural strength and impact energy of flax yarn‐reinforced polypropylene (PP) composites were studied in this work. Highest flexural strength and strength retention were observed for axial (0₆) and cross‐ply (0/90/0)_s laminates, respectively, while also examining the influence of laminate lay‐up and open hole size on flexural strength. It was found that maleic anhydride‐grafted polypropylene (MAPP)‐treated composite laminates achieved marginal improvement on flexural strength for all kinds of laminate lay‐up. Off‐axial laminates (±45₆) showed a good strength retention for open hole laminates after MAPP treatment. The fractography study confirmed microbuckling and matrix crack propagation over the compressive and tensile side of the laminate, respectively. Furthermore, severe surface damage was detected over the tensile side of 8‐mm hole size laminates. Impact test of the flax/PP laminates showed slight improvement by MAPP treatment. High‐ and low‐impact energy was experienced for axial and off‐axial laminates. The damaged impact sample shows evidence of fiber pull‐out for untreated flax yarn reinforced laminates. POLYM. COMPOS., 34:1912–1920, 2013. © 2013 Society of Plastics Engineers     

Gas‐Liquid Mass Transfer in Fibrous Bed Reactor with Counter‐Current Liquid Recycle

In this work, the gas‐liquid mass transfer in a lab‐scale fibrous bed reactor with liquid recycle was studied. The volumetric gas‐liquid mass transfer coefficient, k_La, is determined over a range of the superficial liquid velocity (0.0042–0.0126 m.s^–1), gas velocity (0.006–0.021 m.s^–1), surface tension (35–72 mN/m), and viscosity (1–6 mPa.s). Increasing fluid velocities and viscosity, and decreasing interfacial tension, the volumetric oxygen transfer coefficient increased. In contrast to the case of co‐current flow, the effect of gas superficial velocity was found to be more significant than the liquid superficial velocity. This behavior is explained by variation of the coalescing gas fraction and the reduction in bubble size. A correlation for k_La is proposed. The predicted values deviate within ± 15 % from the experimental values, thus, implying that the equation can be used to predict gas‐liquid mass transfer rates in fibrous bed recycle bioreactors.     

Surface and printing properties of synthetic film papers

We studied the surfaces, including both the composition effects and the processing rates, of polypropylene (PP) composite films used for synthetic paper to determine the surface free energy (γ_s) and the irregularities on the film surfaces. We correlated these two characteristics to the printing quality by assessing the facility with which the offset ink was removed from the surface of the paper and also the ink absorption. Five films with different compositions were uniaxially oriented with a flat‐die extruder at two different stretching rates. The results of scanning electron microscopy (SEM) of the films showed good dispersion and distribution of the filler particles used in the compositions of the films and also of the polystyrene (PS) dispersed throughout the PP matrix. The SEM analysis also revealed slightly high surface irregularities on the film surfaces through a high concentration of CaCO₃, which thus increased the coefficients of static and kinetic friction and the γ_s values. These film properties created better printing quality and also more strongly fixed offset ink onto the film. However, the films with high relative quantities of PS in their composition showed a high polar component in their total γ_s when compared to films with less PS or no PS in their compositions. However, because of the apolar characteristic of the offset printing ink, the ink absorption worsened. The films underwent stretching at two different rates, which did not significantly affect the γ_s values or the friction coefficients; however, they did slightly change the printing quality and ink adhesion. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2346–2355, 2003     

Mechanical and tribological properties of polyoxymethylene modified with nanoparticles and solid lubricants

Polyoxymethylene (POM) composites modified with nanoparticles, polytetrafluoroethylene (PTFE) and MoS₂ were prepared by a twin‐screw extruder. The effect of nanoparticles and solid lubricant PTFE/MoS₂ on mechanical and tribological properties of the composites were studied. Tribological tests were conducted on an Amsler friction and wear tester using a block‐on‐ring arrangement under dry sliding and oil lubricated conditions, respectively. The results showed that generally speaking POM nanocomposites had better stiffness and tribological properties than corresponding POM composites attributed to the high surface energy of nanoparticles, except that the tensile strength of three composites and dry‐sliding tribological properties of POM/3%Al₂O₃ nanocomposite decreased due to the agglomeration of nanoparticles. Tribological properties differed under dry sliding and oil lubricated conditions. The friction coefficient and wear volume of POM nanocomposites under oil lubricated condition decreased significantly. The increased deformation resistance supported the increased wear resistance of POM nanocomposites. POM/PTFE/MoS₂/3%Al₂O₃ nanocomposite had the best mechanical and tribological properties of all three composites, which was attributed to the synergistic effect of nanoparticles and PTFE/MoS₂. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Relationship between adhesion and friction forces

The Surface Forces Apparatus technique was used to measure the normal (perpendicular) and lateral forces between variously prepared surfaces under both dry and lubricated conditions. 'Normal' forces include the force vs distance functions, F(D), for surfaces separated by thin liquid films as well as the adhesion forces and energies, γ, for two surfaces in adhesional contact. 'Lateral' forces include the static and kinetic friction forces F of the surfaces as they slide past each other at a given separation, D. The results show that very thin liquid films confined between two solid surfaces can sustain both normal and shear forces or stresses. The results further indicate that the normal force, F(D) or γ, may be directly related to the static friction force, F_s, and simple equations are proposed that relate these forces (by 'static' friction force is meant the lateral force that must be applied to initiate motion, but not necessarily to maintain this motion). In contrast, the kinetic friction force, F_k, which is the force that must be continually applied to maintain motion at a given velocity, was found to be related, not to the equilibrium or reversible interaction but to the dissipative or irreversible part of the adhesion or interaction energy during a loading-unloading cycle. There is a high degree of correlation in the way that normal forces and friction forces are affected by changes in applied load or pressure, sliding velocity, loading-unloading rates and temperature. These systematic correlations can be conveniently represented by non-equilibrium 'adhesion' and 'friction' phase diagrams.     

An investigation of the friction and wear behaviors of micrometer copper particle‐ and nanometer copper particle‐filled polyoxymethylene composites

Micrometer and nanometer copper particle‐filled polyoxymethylene composites (coded as POM‐micro Cu and POM‐nano Cu, respectively) were prepared by compression molding. The compression strength and tensile strength of the composites were evaluated with a DY35 universal materials tester. An RFT‐III reciprocating friction and wear tester was used to examine the tribological properties of the composites. The elemental compositions in the transfer films and the chemical states of the elements in the composite‐worn surfaces were analyzed with electron probe microanalysis and X‐ray photoelectron spectroscopy, while the surface morphologies were observed with scanning electron microscopy. It was found that Cu( CH₂ O )_n was produced in sliding of a POM‐nano Cu pin against an AISI 1045 steel block and Cu₂O was produced in sliding of a POM‐micro Cu pin against the same counterface. POM‐micro Cu exhibited higher copper concentration in the transfer film compared with POM‐nano Cu, and the transfer film of the former was thick and patchy compared with that of the latter. It was also found that micrometer and nanometer copper particles as fillers in POM exhibit a distinctive size effect in modifying the wear mechanisms of the composites. In other words, the wear mechanism of POM‐micro Cu is mainly scuffing and adhesion, while that of POM‐nano Cu is mainly plastic deformation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2404–2410, 2000     

Kinetics measurements on a stationary disk electrode in a uniformly rotating fluid (SDERF). II. The electron transfer reaction in the Fe(CN)4−6/Fe(CN)3−6-system

The operation of the SDERF-cell in the study of the electron transfer kinetics of the Fe(CN)^4?₆/Fe(CN)^3?₆-system in 1 M KCl and 1 M KNO₃-solutions at a stationary Pt-disk electrode is reported. The experimental current—overpotential curves are recorded by linear sweep voltammetry and analysed by two different methods using the theoretical relationship derived for a stationary disk electrode placed in a free rotating fluid. Both methods give the same value for the experimental rate constant k*. The effects of the temperature (0° to 40°C) and of the ratio of the rotor radius (r_r) to the electrode radius (r_e)(r_r/r_e = 0.50 to 0.81) have been studied. The activation energy for the redox process in 1 M KCl and 1 M KNO₃ are: E_a = 3.4 ± 0.6 kcal/mol and E_a = 3.7 ± 0.7 kcal/mol respectively, while the k*-values at 25°C are: k* = (5.67 ± 0.41) × 10^?3 cm.s^?1 and k* = (4.53 ± 0.29) × 10^?3 cm.s^?1 respectively. The difference from the standard rate constant k₀ ? 0.100 cm.s^?1 is explained by the effect of the cell-geometry characterized by the G-factor, so that k° = Gk*, where G ? 19 for our cell.     

Electrode cleaning and anion effects on ks for K3Fe(CN)6 couple

The effects of 17 different platinum electrode cleaning procedures on the heterogeneous rate of electron transfer (k_s) for the potassium ferri/ferrocyanide couple in 1 M aqueous KCl were investigated. The method yielding the most reproducible/high k_s (0.21 ± 0.04 cm s^?1) values was that of aque regia, pulse (cathodic, anodic, cathodic), and flame. Utilizing this cleaning procedure and the same couple, both cation and anion effects on k_s were examined. The previously noted cation effect on k_s was confirmed with Cs > K > Na > Li. Some discrepancy however, was noted for the tetra-alkylammonium salts. The anion effect was found to be larger than that of cations. Closer examination revealed the effect to be primarily due to adsorption of the halide. This adsorption effect further confirms the cleaning method choice since the method will allow the most halide to be adsorbed thus yielding the highest k_s.