Studies On Synthesis Of A New Chelating Fiber And Using It To Remove The Deleterious Metal Ions From Apple Juice

There are various kinds of mineral substances in the apple juice, such as calcium, phosphorus, iron, chromium, zincum, aluminium, stannum and etc. At the same time, there may be some heavy metal ions such as copper, lead, arsenic, mercury, which are harmful to human body. Although the content of these metal ions is little, especially the harmful metal ions seldom exceeds the standard in apple juice. But the existence of a small amount of metal ions has certain influence on fruit juice quality. Meanwhile, with people's increasing requirement to the fruit juice security, the stricter standard for metal ions, especially for the harmful metal ions will be put forward. So, it is necessary to look for a method to get rid of metal ions suited to continuous manufacture.Chelating fibers are novel exchange fibrous adsorbents, which contain abundant functional groups and can form multi-donor ligand with metal ions. In the functional groups, there are some atoms such as N, O, S, P, which can form more steady complex with the metal ions through coordination. So, the chelating fiber has more strong combinability with metal ions and better selectivity. The chelating fiber is widely used to recovery , concentrate, enrich and separate metal ions. But it has not been reported that chelating fiber is applied in apple juice processing.In order to apply the chelating fiber into the processing of apple juice, a new adsorption and chelating material has been being synthesized, by grafting acrylonitrile and acrycylic acid onto pre-irradiated polypropylene nonwoven fabrics. Electron beam was used as irradiation source. The effect of pre- irradiation dose, reaction temperature, reaction time and monomer concentrate on grafting rate are investigated; The best condition of grafting reaction was confirmed. It was characterized by infrared spectrum (IR), scanning electron microscope(SEM) and element analyzer and etc. The influence of monomer ratio, grafting rate, pH value and adsorption time on adsorption capacity was studied, and the thermodynamics property was analyzed according to model of Freundlich. Kinetics on the adsorption of metal ions from apple juice using this chelating fiber was discussed. Theories and data were supplied to resolve the problems in AJC processing.