Physicochemical pretreatment

Ohrt, J.A. Physicochemical Pretreatment of a Synthetic Industrial Dairy Waste. Lenox Institute of Water Technology Lenox, MA. Masters Thesis (Wang, L.K. Aulenbach, D.B., advisors), 2001 62... 

Ammonia fiber explosion (AFEX) is another physicochemical pretreatment in which lignocellulosic materials are exposed to liquid ammonia at high temperature and pressure for a period of time, and then the pressure is swiftly reduced. A typical dosage is 1-2 kg ammonia/kg dry biomass at 90 °C and residence time of 30 min. To reduce the cost and protect the environment, ammonia must be recycled after the pretreatment. 

The pollutant removal efficiencies of these processes, at different processing stages, are frequently performed by incorporating a variety of chromatographic techniques. For comparison only, AST and radiolytic processes will be considered. AST is a state of the art wastewater treatment process (WWTP) that is preceded by conventional physicochemical pretreatment steps. The level of acidic pharmaceuticals such as carbamazapine, diclofenac, and naproxen in the influent and effluent of an AST facility was monitored by chromatography and the removal efficiency was found to be low.""... 

A biological alternative to the use of physicochemical pretreatments have been proposed recently (Canam, Town, Iroba, Tabil, Dumonceaux, 2013 Lopez-Abelairas... 

Paulova, L., Kacaba, J., Patakova, P., Rychtera, M. et al. (2012) Degradation products formed in physicochemical pretreatment of lignocellulose biomass and their influence on the effectivity of the ethanol production process. Chem. Listy, 106, 626—631. 

Lignocellulose waste hydrolysis to fermentable sugars still brings many challenges, because the degradation of cellulose and hemicellulose are hampered by the structure and composition of lignocellulosic biomass (Himmel et al., 2007). Due to its structural recalcitrance, a chemical and physicochemical pretreatment is a required stage to obtain potentially fermentable... 

NOTE The term pretreatment is generally assumed to refer to some form of permanently installed equipment employed to treat MU water or FW. Such equipment provides physical or physicochemical water conditioning processes (such as ion-exchange softening) and is employed prior to the application of any internal FW or BW chemical treatments. 

The SUM was covered by a polymer film with an orifice of approximately 0.3 mm in diameter on each side, and subsequently a folded BLM was generated from a DPhPC/l,2-dipalmitoyl-in-glycero-3-phosphatidic acid (DPPA) monolayer on the side facing the SUM (Fig. 19). Interestingly, no pretreating of the orifice with any alkane or lipid was required, as is imperative for all other BLM techniques. Thus, an accumulation of such compounds could be excluded, and the physicochemical properties of the membrane and... 

Chemical sample preparation. The most important chemical and physicochemical procedures of sample pretreatment are ... 

In addition, the removal of organic matter and Fe oxides from soils and sediments is common practice as a pretreatment for soils prior to physical, chemical and biological analyses. The effects of the removal of these components on physicochemical and surface chemical properties of soils will be discussed as well. 

In summary, the removal of organic matter and Fe oxides significantly changes the physicochemical and surface chemical properties of soils. Thus, this pretreatment affects the overall reactivity of heavy metals in soils. The removal of organic matter and Fe oxides may either increase or decrease heavy metal adsorption. The mechanisms responsible for the changes in metal adsorption in soils with the removal of organic matter and Fe oxides include increases in pH, surface area, CEC and electrostatic attraction, decreases in the ZPC, shifts of positive zeta potentials toward... 

Silica plates were activated at 120°C for 30 min then cooled in a desiccator. Separations were performed with dichloromethane-methanol mixed in various volume ratios. C18 plates were not pretreated and separation was carried out with mixtures of acetone-water. It was established that both adsortion and RP-TLC can be applied for the separation of tetraphenylporphyrin pigments. Topological indexes may help the better understanding the physicochemical procedures underlying the separation [309],... 

In contrast to GC, liquid chromatography hyphenated with mass spectrometry (LC-MS) does not require a derivatization step before sample analysis. Separation of metabolite from sample matrix is achieved using chromatography columns with various stationary phases of different physicochemical characteristics. LC-MS is more often used than GC-MS because it is more suitable for unstable compounds, compounds difficult to derivatize, and nonvolatile compounds [6, 7]. Therefore, a wider range of metabolites with various physicochemical properties can be determined using LC-MS. Moreover, the sample pretreatment procedure is much simpler, which can have a great impact on minimization of analytical variability. 

Membrane fouling is a complex process where the physicochemical properties of the membrane, the type of cells, the quality of the feed water, the type of solute molecules, and the operating conditions all play a role. The end result of most membrane separations is a fouled surface that the operator will not be able to clean to its original state. To reduce the tendency to irreversible fouling it is essential to operate the plant/unit below the critical flux. This must go hand-in-hand with reliable feed water pretreatment schemes. 

Studies performed on the etherification of potato amylose and amylopectin with (diethylamino)ethyl chloride showed that amylose in the starch granule was more reactive than amylopectin.2429 However, the relative reactivity of both starch components could be changed by physical pretreatment of the granules, for instance, by milling, heat-moisture treatment, freeze-thawing, and chemisorption. The physicochemical properties of amino starches depend on the starch variety reacted 2430 Among potato, sweet potato, rice, wheat, and tapioca starch studied, the last reacted most readily. 

Effects of Pretreatments on Physicochemical Changes of Pried Poods.53... 

EFFECTS OF PRETREATMENTS ON PHYSICOCHEMICAL CHANGES OF FRIED FOODS... 

Furthermore, consolidation of the theoretical basis of microwave pretreatment is a topical goal [133]. New studies on this subject should probably include in-depth investigation of the interaction of microwaves with substances of different chemical nature (solvents, analytical, stmctural components of microwave systems), research into the effect of physical properties of microwaves (frequency and intensity) on the pathway of physicochemical processes in solution and in heterogeneous systems (cf Ref. [134]). 

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