Basis of dry cleaning

Dry cleaning means a cleaning process for textiles, which is done in apolar solvents instead of water. If water is used, such cleaning process is called washing or laundering . 

Natural textile fibers, such as wool, cotton, silk and linen, swell in water because of their tendency to absorb water molecules in themselves. This causes an increase of their diameter and a change of the surface of yams and fabrics. The result is shrinkage, felting and ereasing. 

Because of the apolar character of dry cleaning solvents cleaning aetivity also deals with apolar contamination. Oils, fats, grease and other similar substanees are dissolved in 

To make washing active to clean oils, fat and grease from textiles, soap (detergent) has to be added to water. To make dry cleaning active to clean salts, sugar and the like from textiles, dry cleaning detergent has to be added to the solvent. 

Dry eleaning solvents are recycled. The solvent consumption in modem machines is in the range of about 1 - 2 % per weight of the dry cleaned textiles. 

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The high quality of the fastness properties is the basis for frequent pigment use in textile printing. Dry cleaning with perchloroethylene or washing has almost no effect on the color. P.Y.83, sometimes in the form of a preparation, is used for viscose spin dyeing, secondary acetate, and polyacrylonitrile. 

The XAD-4 quaternary resin was cleaned by Soxhlet extraction and kept wet under water to minimize artifacts from the resin. An oily, yellow residue observed during concentration of the acidic eluants required an additional cleanup step. On the basis of the results of the resin blank experiments, it was necessary to clean the XAD-4 quaternary resin by batch process with saturated HCl/methanol prior to Soxhlet cleaning with solvents. Artifacts such as benzoic acid were found in the resin blank experiments, but, in general, the mass of each artifact (per dry weight of resin) was negligible. 

Despite the widespread use, there are many health, safety, and environmental concerns associated with the use of perc. Perchloroethylene has been described as a probable human carcinogen based on both laboratory animal studies and human epidemiological studies (IARC, 1995). According to the USEPA (1998), there is a reasonable basis to conclude that there can be a health risk for cancer and some non-cancer effects to workers from the relatively high PCE exposures observed on the average in the dry cleaning industry. Risks also exist for apartment residents colocated with a perc dry cleaning facility. 

Assay and test results are determined on the basis of comparison of the test sample with the reference standard that has been freed from or corrected for volatile residues or water content as instructed on the reference standard label. If a reference standard is required to be dried before use, transfer a sufficient amount to a clean, dry vessel. Do not use the original container as the drying vessel, and do not dry a reference standard repeatedly at temperatures above 25°. Where the titrimetric determination of water is required at the time a reference standard is to be used, proceed as directed in the Karl Fischer Titrimetric Method under Water Determination, Appendix IIB. 

The nature of the matrix influences the initial extraction step and choice of solvent. Crops are sometimes classified on the basis of aqueous, dry and oily. For example, samples of low water content might be extracted with a mixture of acetone (miscible with water) and hexane. Samples with a high fat content might be extracted with a nonpolar solvent such as hexane. As with soil samples, further clean-up by liquid-liquid partition and SPE or column chromatography is often necessary. 

Several cleaning techniques exist for the removal of these contaminants (1,2). These techniques can be subdivided into the three classes hot gas cleaning, dry scrubbing/removal techniques and wet scrubbing/removal techniques. Table 1 was used as a structure for the discussion in this workshop. On the basis of this table, the following discussion topics were chosen ... 

At the time of installation, on the basis of information from other ozone plants, it was estimated that the stainless steel tube surfaces would have to be cleaned every 6 months. Only 20 of the 50 units have ever been cleaned. Those uncleaned are not in bad condition. This is the finest evidence of the efficacy of the complete air cleaning and drying. 

ISO 9227 [1] does not specify in detail many necessary parameters and does not determine the precision of such a test method. The precision and accuracy of corrosion determination are influenced by many factors preparation of specimens, conditioning, removal of corrosion products, cleaning, drying, etc. In literature on the corrosion tests we failed to find any information concerning the quality of corrosion tests results. The aim of this paper is to call attention to the problems in the corrosion measurement data quality and the necessity to evaluate the uncertainty for measurement results. We attempted to show the main components of uncertainty of the result in such a measurement on the basis of the experimental evaluation of the corrosivity of the spray test corrosion cabinet by means of reference specimens. 

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