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Treatment of Paper and Pulp Industry Effluents
Published in Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang, Treatment of Industrial Effluents, 2019
Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang
The fatal inhibition of methanogenesis by LCFA can be prevented by adding Ca2+, provided it is done so during the early stages of exposure to a methanogenic population. Koster (1987), using lauric acid, studied the time available after the start of exposure in which to add Ca2+. Lauric acid was chosen as the model long-chain acid because it is the strongest potential inhibitor for methanogens among the acids that can be present in any wastewater (Koster and Cramer, 1987). It was observed that 7.5 mM sodium laurate caused 94% inhibition of methanogens using acetate as the sole carbon source. At an exposure time of zero, there was no inhibition. After 3 min of exposure, 40% of methanogenic activity was lost, while after 20 min of exposure, only 33% of the original methanogenic activity remained. A 6-h exposure period resulted in the retention of 4% of uninhibited activity (Koster, 1987). This was similar to the remaining activity if there was no addition of CaCl2. Thus, it was concluded that, after an exposure time of 6 h, calcium addition did not produce any immediate restoration of methanogenic activity. The necessity of an almost immediate addition of calcium chloride to save the methanogenic potential of the sludge if exposed to lauric acid indicates that the acid interacts rapidly with the sludge. It is conjectured that the rapid disappearance from the solution of lauric acid in the presence of methanogenic sludge was caused by precipitation with calcium and other metal ions from cell contents. This loss of vital ions from the cells could account for the loss of their methanogenic activity (Koster, 1987).
Nanofluids
Published in Efstathios E. Michaelides, Clayton T. Crowe, John D. Schwarzkopf, Multiphase Flow Handbook, 2016
Efstathios E. Michaelides, Yulong Ding
e method of preparation of nano uids and the speci c chemicals used as surfactants in uence signi cantly the formation of clusters and aggregates, and the particle distribution within the suspension. Every laboratory, which chemically manufactures nanoparticles, may use their own methods for the stabilization of their respective nano uids, but the methods are typically not reported in the literature. Some of the methods are even proprietary. Mechanical methods, such as milling and shearing the nano uid, have been used extensively to produce stable nano uids. Electromechanical methods, such as the application of ultrasonic waves (soni cation or ultrasoni cation), have also been used extensively to disperse the nanoparticles and prevent them from aggregating and forming a sediment. Chemical methods are routinely used with a variety of surfactants: examples are sodium laurate, sodium dodecyl benzene sulfonate, sodium dodecylsulfate, and gum Arabic acid. A review of the stability and properties of nano uids (Ghadimi et al., 2011) provides an extensive list of surfactants and stipulates that "...choosing the right surfactant is the most important part of the [preparation] procedure." e choice of chemical surfactants is typically accomplished by a trial and error method. O entimes, the amount or concentration of the surfactants is close or even higher than the concentration of the nanoparticles. is implies that the surfactant must be considered as a component that a ects the thermodynamic and transport properties of the mixture. When the actual concentration of the surfactants in the heterogeneous mixture is not high enough to have its own in uence, the Effect of the surfactants and the method of preparation of nano uids on the Effective conductivity is realized via the size and shape mechanism as in Section 3.3.2. It must also be noted that surfactants and dispersants o en have a lower thermal conductivity than the base liquid. e use of these additives is expected to reduce the Effective thermal conductivity of the nanouid suspension.
Polymer-Surfactant Interaction: Part I. Uncharged Water-Soluble Polymers and Charged Surfactants
Published in E. D. Goddard, K. P. Ananthapadmanabhan, Interactions of Surfactants with Polymers and Proteins, 2018
Since both polymer and surfactant can adsorb on solid surfaces, there has been interest in determining what effect each has on the adsorption properties of the other. Chibowski,38 for example, demonstrated that when PAAm was preadsorbed on calcite, enhanced adsorption of SDS resulted at pH > 8. On the other hand, when present together in solution the polymer depressed the adsorption of surfactant. Chibowski and Szczypa39 have recently extended their investigations to include sodium laurate (NaL) and dodecylammonium hydrochloride (DA). Some reduction in adsorption of PAAm on clay on addition of DDBS has been reported by Bocquenet and Siffert.30 All these effects appear to involve polymer/surfactant interaction. Saunders40 showed that the adsorption of MeC on polystyrene could be inhibited by added SDS. He ascribed the effect to preferential adsorption of SDS on the latex particles, but quite clearly the formation in solution of MeC/SDS-associated species has to be considered in the interpretation of these data. Tadros13 studied adsorption effects on silica of the mixed pairs PVOH/DDBS and PVOH/ cetyltrimethylammonium bromide (CTAB). Although, as would be expected, there are pronounced pH effects with this substrate, several conditions exist under which preadsorbed surfactant enhances the adsorption of the polymer and vice versa. Likewise, substantially increased adsorption of PVOH occurred at several pH values when DDBS was present concurrently with the polymer. Mutual enhancement of adsorption on calcite of sodium oleate/starch pairs was also found by Somasundaran.41 Clear indications of synergism in adsorption on titania were obtained by Ma42 for the strongly interacting pair, PVP/SDS, so long as the concentration of SDS was below 4 × 10−4M, i.e., ~T1. To explain the results, this author invoked the formation of a type of surface complex between PVP and SDS which can occur on titania at a bulk concentration as low as l×10−3M SDS. The formation in solution of higher SDS concentrations of “conventional” PVP/SDS complexes resulted in lowered adsorption of both compounds since the complexes are relatively surface inactive.
Microscale bone grinding temperature by dynamic heat flux in nanoparticle jet mist cooling with different particle sizes
Published in Materials and Manufacturing Processes, 2018
Min Yang, Changhe Li, Yanbin Zhang, Dongzhou Jia, Xianpeng Zhang, Yali Hou, Bin Shen, Runze Li
In this experiment, Al2O3 particles of 30, 50, 70, and 90 nm in diameter bought from nanoparticle manufacturer were added into normal saline, subsequently. The nanofluids were prepared at a volume fraction of 2% through two steps: the prepared nanoparticles were dispersed into normal saline and then a dispersing agent was added following an adequate ultrasonic vibration to prevent nanoparticle agglomeration in normal saline. Approximately 0.2 vol% sodium laurate (C12H23NaO2) was used as dispersing agent. Considering the biocompatiblity of sodium laurate on human body, we will research it further in our studies.