Study On Treatment Of Humic Acid And Tryptophan By GAC-UF Integrated Water Purification Column

With the rapid development of economy,people’s living standard has been improved.The requirement of drinking water quality is getting higher and higher.As soon as the disinfection by-products are discovered,people pay more attention to them.The"three causes"toxicity,which are carcinogenic,teratogenic and mutagenic,will cause great harm to human body.GAC-UF integrated water column,namely granular activated carbon-ultrafiltration integrated water column,is the activated carbon and ultrafiltration two kinds of water purification process combination in a column device,this combination process not only saves the water plant floor space,but also for the loss of energy consumption and cost are greatly reduced.The conventional indexes of drinking water（nitrate nitrogen,sulfate,heavy metal hexavalent chromium,ammonia nitrogen and COD,etc.）have been studied experimentally before,and the removal effect of these conventional indexes is good.If the integrated clean water column has a certain ability to remove the by-products of disinfection in water,it will be of great significance to its practical application in water plant and water treatment field.In this paper,two substances,humic acid and tryptophan,were selected as the representatives of disinfection by-product precursors,and their removal effects were studied by using granular activated carbon and ultrafiltration integrated clean water column.The static experiments on the removal of humic acid and tryptophan by seven kinds of activated carbons with different shapes and iodine values were studied.Static experiment mainly from the influent p H value,adsorption time,the amount of activated carbon,reaction temperature and concentration of raw water five factors of activated carbon adsorption effect of different types of pollutants were studied.According to the static experiment,the activated carbon with the best removal effect was selected and the dynamic experiment of humic acid and tryptophan was carried out with the integrated net water column.The dynamic experiment mainly investigated the removal effect of the integrated net water column on humic acid and tryptophan according to the p H value of raw water,influent flow rate and raw water concentration.The optimum conditions,factors and removal efficiency of humic acid and tryptophan were studied.The main conclusions of this paper are as follows:（1）In the static experiment,the removal effect of activated coke and columnar activated carbon is the best,especially the columnar activated carbon with iodine value of 800.The removal effect of activated coke and columnar activated carbon on humic acid and tryptophan is better when the p H is less than 7.In the experiment,the humic acid removal effect of activated carbon with 800 columnar iodine value and 1100 coconut shell iodine value is better;The removal effect of activated carbon with 800 iodine value and active pyrotryptophan with1000 iodine value was the best.The best removal effect of humic acid is activated coke and activated carbon with 800 iodine value.The removal rate of active tryptophan was 81.92%at2 mg·L^-1 with the best removal effect,and 93.07%at 800 activated carbon with columnar iodine value.（2）The influence of raw water concentration on the removal effect.Coconut shell activated carbon had the best removing effect of humic acid,while activated coke and columnar activated carbon with iodine value of 800 had the best removing effect of tryptophan.The effect of the reaction temperature on the removal effect of humic acid is better activated coke and columnar iodine value of 1000 activated carbon.The removal rate of active pyrotryptophan was 81.33%,and that of 800 activated carbon with columnar iodine value was 74.29%.These two activated carbons have the best removal effect.（3）In the dynamic single factor experiment for ultrafiltration alone,in the inlet flow experiment,the humic acid removal effect was the best when the inlet flow was 160 m L·min^-1,and the humic acid removal rate was the highest when the p H was 5,which was 63.92%.When the influent flow rate was 100 m L·min^-1,the maximum tryptophan removal rate was47.15%,and the maximum tryptophan removal rate was 64.75%when p H=8.The removal effect of humic acid and tryptophan is better when the concentration is higher.（4）In the integrated net water column experiment of activated carbon-ultrafiltration combined action,the influent flow is 160 m L·min^-1 and the reaction time is 6.5 h,the humic acid removal efficiency is the best,and the maximum humic acid removal efficiency is 81.08%when the p H is 5.When the influent flow rate was 120 m L·min^-1,the best removal effect of tryptophan was achieved when the reaction time was 6.5 h,and the maximum removal rate of tryptophan was 55.50%when p H=6.When the concentration of humic acid and tryptophan were 5 mg·L^-1,the best removal effect was obtained,and the removal rates were 42.34%and43.44%.（5）The static experiment and the separate experiment of ultrafiltration membrane show that activated carbon and ultrafiltration have a certain removal effect on humic acid and tryptophan.Static experiment is the basis and premise of dynamic experiment.Through static experiment,it is realized that the best removal effect of activated carbon is when p H<7,and the removal effect of columnar activated carbon is second only to active coke,and the removal effect is better.The dynamic experiment was carried out on the basis of static experiment.Compared with the combined removal efficiency of ultrafiltration and activated carbon,the combined removal efficiency was improved,and the removal efficiency was better when the concentration of humic acid and tryptophan was higher(4 mg·L^-1-5 mg·L^-1).（6）integration of granular activated carbon-ultrafiltration net water disinfection by-products of humic acid and the amino acid tryptophan these precursor of removing effect,mainly is the strong adsorption ability of active carbon,to also have certain ability to remove organic matter,ultrafiltration membrane mainly screening effect,these parts after contact with activated carbon to remove organic substances,They are screened by ultrafiltration membranes to reduce their concentration in water.And the integration of the net water column will be the combination of the two processes,the middle is isolated through a filter screen,not only save the device floor area,and avoid the interference of the two processes,the removal effect is also improved.