Removing Impurities From Fermentation Broth Of Calcium Gluconate And Biomimetic Synthesis Of Nanoselenium

Impurities of the fermented broth of calcium gluconate, such as sugars and proteins, affect quality of the product. It is still aproblem of removal impurities in the fermentation industry. If the problem was solved, the quality of product and economical benefit would be improved radically. Nanoseienium has been widely used in chemistry, biology and optoelectronic-component because of its good bioactivity and excellent electrochemical performance. Especially during the last few years, the different morphologies and corresponding functions of nanoselenium have been attracting more and more attentions.This paper is separated into three parts that are shown as follows:1. Firstly, the content of main impurities, sugars and proteins, in the original fermented broth of calcium gluconate were measured. Secondly, inorganic polyaluminium chloride (PAC) was employed as flocculant to remove the impurities. The removal ratio of total sugars and proteins were used as the evaluating indexes in the orthogonal flocculation experiment. The several factors, such as pH value of solutions, flocculant dosage, mixing speed, and laying-aside time, on the efficiency of impurity remove were investigated. The single factor analysis of PAC dosage and pH value was investigated based on the above orthogonal experiment. Then the effect of concretion-aid agent on the removal ratio of total sugars was studied. The results showed that the removal ratio of sugars and proteins were 81.85ï¼…, 96.42ï¼…, and residual aluminium is 0.1385mg/L, respectively, under the optimum conditions of flocculation. In addition, the mechanism of flocculation with PAC was also discussed.2. In order to remove more sugars from the fermented broth of calcium gluconate, organic PASS was selected to flocculate the impurity. The results indicated that the five factors, i.e. flocculant dosage, pH value of solution, mixing speed, laying-aside time, and the original concentration of PASS mainly affacted the flocculation results, so they were studied in the orthogonal experiment. The removal ratio of total sugars reached 85.14ï¼…in the above optimal condition. Then the cooperated flocculation of PAC/PASS was further investigated on the factor such as dosing sequence and the weight concentration ratio of PAC/PASS. Under the above optimal conditions, the residual aluminium is 0.1222mg/L, the removal ratio of total sugars and proteins could get to 89.90ï¼…, 96.57ï¼…, respectively. The resulut showed that the mixed PAC/PASS as flocculant is better than PAC (or PASS) in removing impurities existed in the fermented broth of calcium gluconate.3. L-cysteine was used as a reductant and a template to prepare nanoselenium at room temperature. The effect of different reactant concentration ratios, reaction time and ultrasonic time on morphologies and crystalline phases of the products were investigated. The products were characterized by transmission electron microscopy (TEM), Ultraviolet-visible spectrum (UV-vis) and X-ray diffraction (XRD). The results showed that spherical amorphic nanoselenium with diameter of 48nm was slowly obtained at room temperature. By means of the high intensity ultrasonic, rod-shaped t-Se was produced. The dynamic experiment displayed that the spherical amorphic Se was formed firstly, then it was quickly changed into grey rod-shaped t-Se by controlling ultrasonic time, The formation mechanism of selenium nanorods was also discussed.