Effect Of Surface Active Additives Research Articles

Effects of Surface Active Additives on the Enzymatic Treatment of Phenol and Its Derivatives: a Mini Review

Phenolic wastewaters represent a serious health and environmental problem. The remediation of phenolic wastewaters using oxidoreductase enzymes has emerged as an attractive environmentally friendly treatment method. However, the loss of enzyme activity during the treatment remains a key limitation. Thus, the aim of this article is to review and assess the recent progress in utilizing surface active additives (i.e., polymers, biopolymers, surfactants, and biosurfactants) for the reduction of enzyme inhibition and, thus, the enhancement of enzymatic remediation of phenolic wastewaters. The reported effect of polymeric and surfactant additives on the enzymatic remediation of phenolic pollutants is mixed. Some studies reported significant enhancements while others demonstrated minimal or no gains. More seriously, it has been reported that these fossil-based additives might lead to a higher toxicity of the treated wastewaters. Bio-based (biopolymers and biosurfactants) additives might address this toxicity issue; however, the bio-based additives are not always as effective as the fossil-based ones. Despite the beneficial effect, with some exceptions, of additives, the enhancement level varies widely, probably due to the variations in the reaction environment. Thus, to draw meaningful and reliable conclusions on which additive(s) is more promising, thorough studies under unified conditions are needed. Additionally, generation of secondary pollutions associated with the fossil-based additives urges the replacement of such additives with bio-based ones. However, the effectiveness of the bio-based additives is still not sufficiently documented, stressing the need for more in-depth studies.

Effect of surface-active additives on the temperature behavior of interfacial tension in water-n-hexane systems

The temperature dependence of interface tension in a water-n-hexane system without additives and after addition of stearic acid was experimentally studied at four different concentrations. A method for determining the excess surface chemical potential from experimental data on the temperature dependence of interfacial or surface tension is proposed for a diluted solution of surface-active impurity. The excess surface chemical potential of stearic acid at the interface of a water-n-hexane binary mixture is determined.

The mechanism of poly(ethylene glycol) 4000 effect on enzymatic hydrolysis of lignocellulose

Adsorption of cellulase on substrates is a key step for enzymatic hydrolysis of lignocellulose. Addition of surface active additives affects the interaction between cellulase and substrates and has been proven to enhance enzymatic hydrolysis of lignocellulose by many studies. However, the mechanism of poly(ethylene glycol) effect is not yet clear. In this study, enzymatic activity and the adsorption of cellulase on different substrates with different addition sequence of PEG 4000 were investigated. The crystallinity index of substrates incubated by PEG 4000 was also measured by FTIR and XRD. Except for reduction of unproductive binding of cellulase on lignin which was reported by some literatures, current results confirmed a crucial function of PEG 4000 which prevented cellulase deactivation on cellulose rather than lignin through significant difference in adsorption capacity and enzymatic activity of cellulase with different PEG 4000 addition sequence. This conclusion rationally explained PEG 4000 had positive effect on pure cellulose without lignin as well as on lignocellulosic biomass. In addition, PEG 4000 was also found to be contributed to promote the removal of amorphous cellulose. These conclusions are helpful to understand the effect of surface active additives and optimize the enzymatic hydrolysis process.

Effect of surface-active additives on wetting and rheology of injection-moulding feedstocks

Effect of surface-active additives on wetting and rheology of injection-moulding feedstocks

The effect of surface-active additives on bubble coalescence in aqueous media

An experimental study has been aimed at examining the coalescence phenomena in aqueous solutions of aliphatic alcohols and electrolytes and at determining the effect of these surface-active compounds on bubble coalescence in viscous aqueous media with Newtonian and non-Newtonian behaviour, represented by aqueous solutions of 50 and 60 wt%, saccharose, and 0.2 and 0.5 wt%, xanthan, respectively. Bubble coalescence in aqueous solutions of alcohols and electrolytes was significantly hindered by increasing solute concentration and the coalescence percentage ψ exhibited sharp transition from 100% of bubble pairs coalescing to very low values ( ψ⩽10%) over a narrow concentration range. Transition concentrations of respective surface-active additives, characterising suppression of coalescence in their aqueous solutions, were successfully correlated as a function of the term [σ n(∂σ/∂c) −2] , with exponent values n= 1 3 and 1 4 (or 1 6 ) for solutions of alcohols and electrolytes, respectively. The inhibitory effect of alcohols on bubble coalescence increased with the increasing length of the carbon chain and their transition concentrations were successfully correlated as a function of the number of carbon atoms in the alcohol molecule, c t=31n −7.2 C . The addition of aliphatic alcohols to fully coalescent viscous solutions of saccharose and xanthan modified significantly coalescence behaviour in these viscous media. Transition concentrations of individual alcohols in 50 wt% saccharose solution and 0.2 wt% xanthan solution were very close to those observed in aqueous alcohol solutions, further increase of medium viscosity resulted, however, in an increase of transition concentrations up to an order of magnitude. The character of their dependence on the number of carbon atoms in the alcohol molecule ( c t∼n b C ) remained, however, unchanged for all viscous media studied and values of exponent varied only slightly between −7.1 and −7.7. The effect of electrolytes on bubble coalescence in viscous media was less significant, as compared with the alcohol additives, and differed with the nature of medium.

The effect of surface active additives on bubble coalescence and gas holdup in viscous aerated batches

An experimental study has been aimed at examining the possibility of modifying the behaviour of viscous liquids in bubble column reactors by addition of surface active compounds (aliphatic alcohols). Results of coalescence measurements showed that bubble coalescence in viscous saccharose solutions could be fully suppressed by addition of alcohols. The transition concentrations of individual alcohols were within the whole set ethanol–octanol successfully correlated as a function of the number of carbon atoms in the alcohol molecule. The bubble column experiments proved that the properties of viscous aerated liquids could be significantly modified by the addition of relatively small amount of alcohol ( c A ≃1×10 -5–1×10 -2 kmol m -3). The results of gas holdup measurements indicated significant increase of bubble bed voidage with increasing alcohol concentration. Fitting of gas holdup data with the Zuber and Findlay drift-flux model also implied favourable effect of the surface active additives on the radial uniformity of voidage profiles, indicated by decreasing values of the distribution parameter, C o. The effect of alcohol addition increased with increasing viscosity of the original medium and was most pronounced in highly viscous saccharose solutions ( μ L ⩾100 mPa s). In full agreement with the results of the coalescence studies, the favourable effect of alcohols on bubble bed voidage increased with increasing length of the carbon chain. Comparison of gas holdup data obtained with different distributor plates indicated significant synergistic effect of alcohol concentration and the mode of primary gas dispersion on the properties of resulting bubble bed and on the values of its voidage. Addition of alcohols thus compensated even for the negative effect of liquid viscosity on the formation and stability of the homogeneous bubbling regime.

Effect of surface active additives on rheology of stainless steel feedstock: L.Nyborg et al. (Chalmers University of Technology, Göteborg, Sweden.)

Effect of surface active additives on rheology of stainless steel feedstock: L.Nyborg et al. (Chalmers University of Technology, Göteborg, Sweden.)

Effect of surface active additives on partitioning of proteins and enzymes in poly(ethylene glycol)/dextran aqueous two-phase systems

The effect of anionic (sodium butylbenzene sulfonate, sodium butylmonoglycol sulfate), cationic (tetrabutyl ammonium bromide), nonionic(Tween 20) and amphoteric (proline) surface active additives on the partitioning of proteins and enzymes, such as BSA, lysozyme, glucose oxidase and β-lactoglobulin, in a bipolymeric aqueous two-phase system of polyethylene glycol and dextran has been studied. The partitioning of proteins and enzymes in the aqueous two-phase system is influenced by surface active additives depending upon their structure and charge. The amphiphiles themselves partition unevenly between the two phases. Their effect on protein partitioning can be explained on the basis of electrostatic and hydrophobic interactions. In the presence of ionic amphiphiles, proteins have an affinity for the other phase if an amphiphile carrying a charge of the same sign partitions to that phase. The hydrophobic effect contributes to protein partitioning if the proteins have significant members of surface hydrophobic amino acid residues. © 1998 Society of Chemical Industry

Effect of surface active additives on partitioning of proteins and enzymes in poly(ethylene glycol)/dextran aqueous two‐phase systems

Effect of surface active additives on partitioning of proteins and enzymes in poly(ethylene glycol)/dextran aqueous two‐phase systems

The Effect of Surface Active Additives on the Partitioning of Proteins and Enzymes in Aqueous Two‐Phase Systems

The effect of cationic and anionic surface active additives on the partitioning of proteins has been studied. The surface active agents interact with proteins electrostatically and also hydrophobically. The increased hydrophobicity of the proteins because of association with surfactants is responsible for the changes in the partition coefficients and in some cases for precipitation of the proteins. Specific interactions also exist between mildly surface active amino acids and proteins.

The Effect of Surface Active Additives on the Partitioning of Proteins and Enzymes in Aqueous Two-Phase Systems

The effect of cationic and anionic surface active additives on the partitioning of proteins has been studied. The surface active agents interact with proteins electrostatically and also hydrophobically. The increased hydrophobicity of the proteins because of association with surfactants is responsible for the changes in the partition coefficients and in some cases for precipitation of the proteins. Specific interactions also exist between mildly surface active amino acids and proteins.

Application of Surfactants to Improvement of Viscose Processability of Sulphate Dissolving Pulp (II)

To follow the previous report, the various effects of surface-active additives upon the viscose processing performance of the sulphate dissolving pulp were observed.Some kinds of non-ionic and anionic surfactants have given definite improvements to the viscose processability of sulphate dissolving pulp, the extents varying according to analytical qualities and chemical reactivities of the pulps used.The functions of nonionic surface additives are related with the chain-length of their hydrophile radicals, and the most favorable range of chain-length of ethylen oxide for the surface active additive was observed to come between 30 and 50 mols in case of the nonionic surfactants used in this experiments.In order to ascertain how surfactants function in viscose processes, a nonionic surfactant was applied in various stages of viscose preparation. The best results were obtained when the surfactant was added at the shredding of alkali cellulose. It is presumed that the improving effects of surfactants for filterability of viscose is mainly attributed to their function as a aid for xanthation reaction and dissolving of xanthate.The floating tendency once incited in the steeping liquor of the pulp sheets when treated by surfactants has been practically lost after the seven months' storage of the pulp sheets.