about 47 khz the paper strips were removed from the first bottle and transferred to another containing fresh solvent ultrasound treatment was continued for another five minutes it was found that the majority of the ink was removed in the first stage for all solvents collection of the suspended ink particles was accelerated by immersing a magnetic stirrer in the bottle this procedure was repeated several times to accumulate enough deinked strips for making handsheets as a control the same paper that had passed through the laser printer but not printed was used both the deinked samples and controls were soaked in water overnight and made into handsheets in the usual manner table i illustrates the results of the solvent screening study the deinking results recorded for each solvent were achieved with an ultrasound treatment time of from about 1 10 minutes at a frequency of about 47 khz longer times were used on the solvents which gave poor deinking performance for the best solvents deinking was substantially completed in from about 1 5 minutes table 1______________________________________solvent screeningsolvent deinking results______________________________________ketones acetone goodacetyl acetone goodacetophenone excellentdiisopropyl ketone excellentcyclohexanone excellentmethyl ethyl ketone mek excellent2 pentanone excellent3 pentanone excellentcyclic ethers 1 4 dioxane excellent1 3 dioxolane excellenttetrahydrofuran thf excellentesters n butyl acetate excellentethyl acetate excellentdimethyl malonate fair deinkinghexyl acetate goodaromatic hydrocarbons toluene goodxylene goodterpenes citral goodd limonene good u03b1 pinene fair deinkinghalogenated hydrocarbons carbon tetrachloride excellentchloroform excellentmethylene chloride goodcyclic amide cyclic amine n methyl pyrrolidone excellentmorpholine excellentmiscellaneous goodcarbon disulfidealcohols reagent alcohol very little deinkingveratryl alcohol 3 4 no deinkingdimethoxylbenzyl alcohol alicyclics cyclohexane fair deinkingcyclohexene goodaqueous systems 5 n 40 dispersant in 0 5 n no deinkingnaoh20 polyvinyl pyrrolidone no deinking50 18.