Research On The Migration Rule And Mechanism Of Heavy Metal Lead In Ceramic Food Contact Materials

As an important food contact material,domestic ceramic has been widely used in the food packaging industry;however,ceramic food packaging containers with improperly formulated glazes could release some toxic heavy metals such as lead and cadmium into foods,which would contaminate the foods and even endanger consumer's health.With the further development of the ceramic industry,the country has begun to attach importance to the safety research on ceramic food contact materials.Our country's newly promulgated standards and standards for the dissolution limit of heavy metal in ceramic food contact materials have reduced the limit of the dissolution of heavy metals,lead and cadmium,and changed testing methods and indicators.At the same time,research in our country on the mechanism and model of heavy metal migration in ceramic food packaging materials needs at the starting stage and needs to be improved.The purpose of studying the migration mechanism and model of heavy metals is to solve the safety problems of ceramic food contact materials,formulate more scientific food standards,and improve the level of comprehensive supervision.The main research contents and conclusions are as follows:Establishment of migration tests method of heavy metal from ceramic food packaging material.Lead was selected as the heavy metal element for the main research,and a sheet-like ceramic sample was prepared at a firing temperature of 1020.Four kinds of acetic acid,citric acid and lactic acid were selected as food simulants,and the total immersion migration experiments were performed with ceramic samples from six kinds of storage temperature.The storage time was set to 240 h.Inductively coupled plasma emission spectroscopy(ICP-OES)was selected as the detection method of metal concentration in the eluate.Migration law of leading released from ceramic food contact materials into acidic food simulants.The objective of this study was aimed to that explore the migration law of lead from ceramic food contact materials into different acidic food simulants based on time,pH of food simulants and temperature.Results showed that leading released into the leachate was positively with time and temperature.The effect of temperature on leading release is in consistent with Arrhenius' law.When the leaching time is short,lead leaching process is controlled by the term but giving sufficient leaching time,the t-term dominates the leaching process.The amount of lead released became high with decreasing pH of food simulants and the effect of pH on the amount of lead released conforms to a logarithmic function.The discussion of migration mechanism of heavy metal into food.With reference to the migration mechanism of heavy metal in glass,combined with the migration test rule,the migration mechanism of heavy metal lead in ceramics was investigated.Through analysis,it was found that the ratio of lead to silicon in the glaze layer was less than the ratio of lead to silicon in the dissolution solution.The results indicate that the migration mechanism of heavy metal from ceramic glaze is a diffusion controlled ion exchange process.Mathematical forecasting model of the release of leading in ceramic food contact materials.According to the migration rule and migration mechanism obtained from the analysis of migration experiment data,a mathematical prediction model for the migration of heavy metals in ceramic food contact materials based on storage temperature,pH value and storage time was established using the acetic acid test.It is proved that this mathematical model for predicting lead migration has a high degree of fitting and strong versatility,and can well describe the migration of heavy metal lead.