A New Method Of Evaluating Scale Inhibitors And Synthesis Of A New Environmental Friendly Scale Inhibitor

At present time, scale inhibitors are widely applied to control or alleviate the scaling in industries. The worsening of working conditions due to the shortage of water resources brings a great challenge to the development of scale inhibitors. The traditional static test- complexometric titration, which is extensively applied to evaluate the inhibition efficiency, is limited in its application area and time consuming for its operation. On the other hand, the research and development of non-phosphorous and environmentally friendly water treatment agents must be one important trend because of strictly environmental protection laws. Therefore, the present thesis is focused on these two aspects.In the first part of the present thesis, the trend in the change of cations and anions concentration during the precipitation of calcium carbonate was studied, and a new method of evaluating scale inhibitors'efficiency was proposed via acid-base titration. The basic principle of this new method was to evaluate the efficiency of a scale inhibitor by monitoring the change of HCO3- concentration before and after the static scale-inhibition test. The inhibitor efficiency of several inhibitors was evaluated by using the new method with satisfactory results.Polyepoxysuccinic acid, as a novel green water treatment agent, has excellent calcium carbonate scale inhibition and biodegradability. Because of its single functional group, it is not an agent with a dose of multi-effect function. Based on literature survey, we expected that polymeric scale inhibitor's capabilities in calcium phosphate scale inhibition would be improved if hydroxyl groups were introduced into the polymer's molecular. In the second part of the present thesis, sodium hydrogen epoxysuccinate was synthesized by epoxidizing maleic anhydride, and the epoxysuccinate-2,3-epoxy-1-propannol copolymer was prepared by copolymerization in the presence of the initiator-calcium hydroxide. The structure of the monomer and copolymer were confirmed by IR. The performances of the new inhibitor were evaluated by using our new method. It was found that the new scale inhibitor showed better inhibition efficiency to both calcium carbonate scale and calcium phosphate scale.