From compressibility to structural investigation of sodium dodecyl sulphate — Part 2: A singular behavior under pressure

Investigations were carried out to elucidate the compression behavior of a powdered surfactant, sodium dodecyl sulphate (SDS), based on a comparison with the main component of a detergent formulation, i.e. the chorine provider (DCCNa). The energetic analysis based on the compression cycles highlighted a lower compressibility of SDS compared with DCCNa, especially due to its worse packing ability, larger elasticity and bad cohesion ability. Also, it pointed out that the pycnometric density seemed to be overrun under pressure whereas a residual porosity had been evidenced in the expanded tablets. DSC/DTA analysis, Raman spectroscopy as well as powder X-ray diffraction refuted the hypothesis of a physico-chemical transformation of SDS under pressure. This was in accordance with the morphology of the SDS particles, quite unchanged after compression. The pycnometric density measurements have been improved; firstly, it allowed to properly express the compaction ratio of the ejected SDS tablets, and secondly, it led to conclude to a reversible intrinsic compressibility for pressures higher than 50 MPa, explained by the predominant elastic behavior of SDS.     

在硫酸钠熔盐中合成莫来石晶须

采用Al2(SO4)3·18H2O和SiO2作为反应原料,在Na2SO4熔盐中合成了莫来石晶须,利用XRD、FESEM和SEM等手段研究了合成产物的组成和形貌,并研究了合成温度(700℃、800℃、900℃、950℃、1000℃、1100℃和1200℃)、熔盐用量(反应料与Na2SO4的质量比分别为2:1、1:1、1:2和1:4)、保温时间(2h、3h和4h)等工艺因素对合成反应的影响。结果表明:用熔盐法合成的莫来石不含其他晶相,纯度高,晶须直径在50～150nm,长度为3～8μm。研究还发现:Na2SO4熔盐的合适用量为反应料与Na2SO4的质量比是1:1,此时,混合料在900℃开始生成莫来石,950℃石英相基本消失,1000℃保温3h合成反应基本完成,超过1100℃时,合成的莫来石开始分解。因此,熔盐法合成莫来石的合理温度为1000℃保温3h。     

From compressibility to structural investigation of sodium dodecyl sulphate — Part 1: Powder and tablet physico-chemical characteristics

As a part of a study on detergent tablets, investigations were carried out to elucidate the compression behavior of a powdered surfactant, sodium dodecyl sulphate (SDS), based on a comparison with the main component of the formulation, i.e. the chorine provider (DCCNa). The compacted SDS exhibited poor cohesion as well as delayed dissolution whatever the compression pressure. The microscopic observations and the mercury porosimetry measurements both demonstrated that a residual porosity existed in the tablets but the dissolution times were always long. A modification of SDS in contact with water, forming a structure like a gel, probably occurred, inducing the closing of the pores and thereby limiting the water intrusion into the tablets.     

高浓度钠盐对废水生物处理系统的失稳影响综述

废水中含有高浓度溶解性盐是目前许多工业废水的一大水质特征,也是大多数废水水生物处理系统失稳的主要原因之一。作者比较全面的阐述了高浓度钠盐（ＮａＣ１、Ｎａ２ＳＯ４、ＮａＡｃ）对废水生物处理系统的影响,并为保证现有废水生化系统的有效动作提出了相应的改进措施。     

Phenylonium salts as third component of the photoinitiator system safranine O/triethanolamine: A comparative study in aqueous media

The efficiency of the photoinitiator system composed of safranine and triethanolamine for the polymerization of acrylamide in water was improved by the incorporation of onium salts. The phenylonium salts employed were diphenyliodonium chloride, triphenylsulfonium triflate, tetraphenyphosphonium chloride and tetraphenylarsonium chloride hydrate. Among them, diphenyliodonium presents the highest efficiency, followed by triphenylsulfonium. In an appropriate concentration of triethanolamine, the behavior of the sulfonium salt resembles that of iodonium. Tetraphenyphosphonium and tetraphenylarsonuim have little effect over the polymerization rate; however, interesting effects over the photophysical properties of the system were found. Two important conclusions emanate from the work: the phenylonium salts studied aggregate in water in a behavior similar to hydrotropes and several factors contribute to the accelerating effect of the onium salt on the polymerization rate. The main differences in the observed efficiency of the salts might reside in the redox potentials of the salts and in their ability to prevent the photobleaching of safranine in the presence of triethanolamine.     

Novel carboxyethyl amine sodium salts as draw solutes with superior forward osmosis performance

A series of carboxyethyl amine sodium salts (CASSs) with different carboxyl group numbers are synthesized as draw solutes for forward osmosis (FO) application. Their chemical structures are examined by ¹HNMR and HRMS. FO performances are investigated and compared in terms of different physicochemical properties. The effects of the CASS concentration on the osmotic pressure and viscosity of the draw solutions, as well as the resulted FO performance are also systematically investigated. A high water flux of 23.07 LMH and an acceptable reverse salt flux of 0.75 gMH can be achieved with 0.5 g mL^?1 triethylenetetramine hexapropionic acid sodium (TTHP‐Na) draw solution under PRO mode, which is superior to most other draw solutes reported in previous literatures. TTHP‐Na draw solution is further evaluated to recycle the Congo red solution via FO process to examine its applicability for waste water treatment. © 2015 American Institute of Chemical Engineers AIChE J, 62: 1226–1235, 2016     

Effect of electro-chemical properties of sodium salts of various anions on their diffusional parameters in symmetrical cellulose acetate membranes

A relation was obtained between electro-chemical properties of sodium salts (NaCl, NaBr, and Na₂SO₄), and the thermodynamic property of permeability in symmetrical cellulose acetate membranes, the distribution coefficient K and the kinetic property, the overall diffusion coefficients D. K and D were obtained by the method we proposed using measured unsteady- and steady-state dialysis data. The K values increase with the increase of water content and are in the range of 10⁻² for sodium halides and 10⁻³ for Na₂SO₄. D is found to increase with the increase of the solute concentration, and the extrapolated values of D to zero concentration D⁽⁰⁾ are obtained as 0.015–0.03 μm²/s and increase with the increase of water content in the membrane. D can be divided into the concentration independent diffusion coefficients in the dense part of the membrane D_d and in the porous D_p, applying a two-part (perfect or dense and imperfect or porous) model of the membrane. Contrary to D_d, D_p increases with the increase of W_w and can be correlated as D_p,c = _d exp (γ × W_w). It is shown that the averaged D_d, _D increases with the increase of the quantity of the ionic mobility u of the solutes at infinite dilution divided by valence, and that the parameter γ increases with the increase of the ionic mobility u. The value of K increases slightly with the increase of water content and decreases with the increase of the Flory—Huggins parameter χ. The Flory—Huggins parameter χ is calculated from the measured values of distribution coefficients and data obtained from the literature. And it was found that the gradient of linear decrease of χ (λ_cation) depends on equivalent ionic conductivity of anion of salt, λ_an.     

Accelerating effect of NaNO2 on the polymer plating of 6‐substituted‐1,3,5‐triazine‐2,4‐dithiol mono sodium salts

Organic polymer plating properties of 6‐substituted‐1,3,5‐triazine‐2,4‐dithiol mono sodium salts were investigated in the presence of various supporting electrolytes. Among these, the NaNO₂ supporting electrolyte greatly accelerated the film formation rate in polymer plating. The accelerating effect of NaNO₂ was further confirmed by comparing plating potentials in the presence of NaNO₂ and Na₂CO₃. The potentiostatic polymer plating of DAN in the presence of the NaNO₂ supporting electrolyte took place in the potential range of 1.65–1.8 V (compared against saturated calomel electrode reference). Film formation was influenced by such factors as the pH of solution and both the chemical structure and the concentration of triazine dithiol. In polymer platings, NO anions are thought to be electrochemically oxidized to yield NO radicals and these radicals react with DAN to yield new thiyl radicals. The thiyl radicals in the DAN molecules couple with each other by means of disulfide bonds, resulting in the growth of polymer film. Organic polymer plating films are shown to contain disulfide bonds, monosulfide bonds obtained by the reaction between allyl groups and thiyl radicals, and network chains. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2300–2309, 2001     

不锈钢酸洗废水钙钠中和沉淀与碳热还原协同处理新工艺

通过研究不锈钢酸洗废水体系中氟离子脱除和金属离子沉淀的规律,开发了钙钠协同沉淀新工艺,并对新工艺产生的污泥于1200℃下进行还原,细磨、磁选后得铁、铬、镍合金粉末和再生萤石矿。结果表明,该工艺实现了废水的达标排放,污泥产生量减少了14.79%,实现了铁铬镍的金属化还原,得到了再生萤石矿和金属品位93.62%的合金粉末,合金粉末中铁、铬、镍品位分别达69.31%, 7.60%和16.71%,回收率分别高达95.30%, 88.70%和97.53%。     

A new insight into the mechanism of influence of different inorganic salts on optical properties of water‐soluble cationic conjugated polymers

The water‐soluble conjugated polyelectrolyte poly{2,5‐bis[3‐(N,N,N‐triethylammoniumbromide)‐1‐oxapropyl]‐1,4‐phenylenevinylene} (P2) was synthesized and the influences of different inorganic salts on the optical properties of the polyelectrolyte were studied. New absorption and emission peaks at longer wavelength can be observed in the case of P2 with addition of different concentrations of Cl^? or NO₃^?, whereas addition of I^? or ClO₄^? only induces a red shift. Interestingly, addition of SO₄^2? or F^? does not result in considerable changes in optical spectra. Through UV‐visible spectrometry, photoluminescence, ¹H NMR and cyclic voltammetry, we showed that the nature of the inorganic salts brings these different changes. The special structure of the bond of NO₃^? and the large electronegativity of chlorine lead to an electron transfer between the conjugated polymer and the negative ions. The large radius of I^? and the weak electron withdrawing ability of ClO₄^? only bring a red shift of optical spectra. In addition, SO₄^2? and F^? do not affect the spectra significantly, except that the fluorescence intensity falls slightly indicating that P2 is not sensitive to these ions. Copyright © 2011 Society of Chemical Industry     

A further method for chloride analysis of cement and cementitious materials — ICP-OES

This paper describes the novel application of inductively coupled plasma-optical emission spectroscopy (ICP-OES) for the analysis of the chloride content in various South African cements and cementitious materials. Samples were introduced into the plasma as slurries, with and without 5% (v/v) nitric acid. They were agitated in an ultrasonic bath for 10 min to fully disperse and stabilize the slurries. Calibration was performed by using aqueous solutions of reference materials. Measurements were made on a simultaneous SpectroCIROS^CCD ICP-OES with side on plasma. The accuracy of the chloride determination was verified by the analysis of certified reference material. The findings of this investigation are compared with results obtained for the chloride content by the standard EN196-2 indirect Volhard titration and potentiometry with an ion-selective electrode (ISE), previously described as the preferred method. The results obtained with potentiometry and ICP-OES of various commercially available cements were comparable.     

Synthesis of diethyl carbonate from ethanol through different routes: A thermodynamic and comparative analysis

In this study, thermodynamic analysis of various possible synthesis routes of diethyl carbonates (DEC), a benign organic carbonate, was carried out and a comparative analysis was performed. Chemical equilibrium constants at standard conditions were calculated using Gibbs free energy of the system. The Benson group contribution method was used to estimate standard heat of formation and standard entropy change of some raw materials/components like dimethyl carbonate. Variation of heat capacity (C_p) with temperature was estimated for different components from the Rozicka‐Domalski model. Variation of chemical equilibrium constants with temperature and pressure was studied for various routes. Synthesis of DEC from ethylene carbonate (EC) was also found to be better considering equilibrium constants at room temperature. The CO₂ route was found to be the most unfavourable route for DEC synthesis due to stability of CO₂ molecules. Moreover, DEC synthesis through the urea route was found to be best at high temperatures since the equilibrium constants were found to increase exponentially. Experiments were conducted for DEC synthesis using the EC route at two temperatures. Activity coefficients were calculated using the UNIFAC model. Experimentally and theoretically determined chemical equilibrium constant values were found to be similar. PRO/II was also used to minimize Gibbs free energy of the system and estimate the equilibrium constants and the results were comparable with those obtained by the equilibrium constant method and the trend was found to be the same for both the methods.     

Pervaporation separation of IPA‐water mixtures through 4A zeolite‐filled sodium alginate membranes

Incorporation of zeolites into natural polymers has been shown experimentally to enhance both the flux and selectivity in pervaporative dehydration separation of organic compounds. Pervaporation is a promising membrane technique for separation of volatile organic compounds (VOCs)/water mixtures. In this study, hydrophilic sodium alginate (SA) mixed membranes were prepared using solution casting technique by incorporating zeolites into the polymer matrix. The prepared membranes were characterized by ATR‐Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), Thermal Gravimetric Analysis (TGA), and differential scanning calorimetry (DSC) were tested in a laboratory scale pervaporation experimental set‐up. The effect of experimental parameters such as the type and composition of zeolites on permeation flux and selectivity was investigated. When tested on IPA‐water mixtures, the zeolite‐filled membrane was found to give much higher selectivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A New Type of Dispersant [Sodium Salt of Styrene–Methacrylic Acid Copolymer (SSMA)/Montmorillonite (MMT) Nanocomposite] for Pesticide Water Dispersible Granules

A new type of dispersant [sodium salt of styrene–methacrylic acid copolymer (SSMA)/montmorillonite (MMT) nanocomposite] with different content of the MMT was synthesized through in situ solution free radical copolymerization. X‐ray diffraction measurements and electron microscopy observations prove that SSMA molecules can enter the interlayer space of MMT and form an intercalated structure. There are both fully intercalated and partly intercalated structures in the nanocomposites, which are related to the loading content of MMT. Transmission and scanning electron microscopy images indicate that the exfoliation degree of MMT in the nanocomposites decrease with increasing MMT content. Infrared spectroscopy (FTIR) analysis shows that there are hydrogen‐bonding interactions between carboxyl groups of SSMA and hydroxyl groups of MMT. Atrazine water dispersible granules were prepared by using SSMA/MMT nanocomposite as dispersant and their suspensibility in aqueous solution was determined to evaluate the dispersion properties of the nanocomposite. The results show that the addition of MMT can not only increase the steric effect of the SSMA to improve its dispersion properties, but also reduce the production cost of SSMA. The optimum loading content of MMT is 10 wt%.     

A comparative study on co-combustion performance of municipal solid waste and Indonesian coal with high ash Indian coal: A thermogravimetric analysis

In recent years there has been an increasing utilization of coal blends in the Indian power industry, with Indonesian coal, due to high ash content and shortages in domestic coal production. On the other hand, rapid economic growth is aggravating the municipal solid waste (MSW) related environmental problems. In this study, an attempt has been made to compare the co-combustion characteristics of hydrothermally treated MSW and Indonesian coal with high ash Indian coal, so as to replace the Indonesian coal with MSW. The effect of blending Indonesian coal and hydrothermally treated MSW with Indian coal on ignition behavior was studied. MSW blends of 10%, 20%, 30% and 50% (in wt.%), and an Indonesian blend of 10% with Indian coal were tested in a thermogravimetric analyzer (TGA) in the temperature from ambient to 700 °C with a temperature increase of 10 °C/min. From the results, at 10% of blend, ignition and carbon burnout were similar for Indonesian and MSW blend, analogous to coal combustion and even better than the Indonesian coal blend, which indicated the feasibility for replacing Indonesian coal with hydrothermally treated MSW. Further, the results show a scope to increase the MSW blend in Indian coal up to 20%, as the constituents behave as a single fuel.     

Dynamic mechanical thermal analysis of biocomposites based on PLA and PHBV—A comparative study to PP counterparts

The primary objective of this study was the investigation of thermo‐mechanical behavior of cellulosic fiber reinforced polylactid (PLA) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) biopolymers. Both PLA and PHBV were processed with 30 wt % of cellulosic fibers; moreover, to improve the processability and mechanical performance, PHBV was previously blended with 30% by weight poly(butylene adipate‐co‐butylene terephthalate) (PBAT). Secondary target was the comparison of the obtained results to natural fiber reinforced polypropylene (PP) composites reinforced with exact the same fibers and processed by using identical techniques. For validation the thermo‐mechanical properties, a dynamic mechanical thermal analysis (DMTA) was applied. Storage modulus (E′), loss modulus (E″), and loss factor (tan δ) were determined. The DMTA results indicate decreased polymer chain motion with resulting improvement of stiffness expressed by the storage modulus. Finally, the effectiveness of fiber on the moduli was investigated. The C coefficient differs in dependence on fiber type, use of coupling agent, and the reference temperature in glassy state. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3175–3183, 2013     

A study on lithium transport through fractal Li1−δCoO2 film electrode by analysis of current transient based upon fractal theory

Lithium transport through fractal Li_1−δCoO₂ film electrode was investigated in a 1 M lithium perchlorate (LiClO₄)-propylene carbonate (PC) solution by analysis of current transient based upon fractal theory. For this purpose, two kinds of Li_1−δCoO₂ films were deposited by rf magnetron sputtering method on the substrates with different roughnesses. From the analysis of AFM image by the triangulation method, it was found that two Li_1−δCoO₂ film electrodes have the self-similar scaling properties with different spatial outer cut-off ranges. From the analysis of the potentiostatic current transient, it was recognised that the cell-impedance-controlled constraint at the electrode surface is changed to the real potentiostatic boundary condition (diffusion-controlled constraint) when the applied potential step exceeds a critical value and simultaneously the internal cell resistance is below a certain value in the region of single-β-phase. In addition, from the comparison between the cathodic current transients obtained from two fractal Li_1−δCoO₂ film electrodes, it was experimentally confirmed that the current transient shows the generalised Cottrell behaviour before the temporal outer cut-off of fractality, followed by a linear relationship with the slope of −0.5 after the temporal outer cut-off of fractality, when the real potentiostatic boundary condition is maintained at the electrode surface.