| Hair is hydrolyzed by strong acid into amino acids,mainly of glutamic acid,aspartic acid,glycine, alanine, proline, serine, threonine,valine et al.Wastewater of hair hydrolysis one kind of aqueous solution rich in multiple amino acids,in which, cystine, tyrosine, leucine and basic amino acids have been separated by different methods.The lack of research might not only affect the use of amino acids,but also cause resource waste and environment pollution.Because of the higher price of the calcium amino acid compound,the third generation of calcium supplement,its application is restricted.This paper developed synthesis conditions of calcium amino acid compound,among the amino acids is derived from wastewater of hair hydrolysis. This method can not only reduce the cost,but also realize the circulation utilization of rejectamenta of animals.The main contributions are as following:1. The main composition of the hair hydrolyzing liquid and the best condition for decoloration with the decolorization rate as indexes of the hair hydrolyzing liquid was studied. The results showed that the total solid contents were 15.41%,the total nitrogen contents were 2.77%, the total amino acid contents were 324 g·L-1, the ammonium chloride contents were 5.67%, with lower mineral elements. The activated carbon was determined as the best decoloring agent by comparing the absorbance of the hair hydrolyzing liquid at the wavelength of maximum absorption. On the basis, the best technological process of decoloration: adding 8%(m/v) active carbon to the hair hydrolyzing liquid at 90℃, with p H at 3.0 and decoloring the solution for 50 min was determined. The decolorization rate was 86.31%, and the retention rate of amino acids was 94.92%.2. The effect of the molar ratio of amino acid and calcium ion, the chelate temperature, time and p H value on the chelating reaction were investigated in water system.The optimal reaction conditions were established by single factor experiment and orthogonal experiment:that the optimal temperature was 60℃,time 60 min, the molar ratio of ligand of compound amino acid to calcium cation 2∶1 and p H 8.Under these conditions, the chelating rate was 90.42%.3. By comparing the UV spectrum of amino acid and calcium amino acid compound, it was proved that the chelation reaction between amino acid and calcium.And it was drawn new material could be obtained by comprehensive comparison. It was proved that the-NH2 and the-COOH bond in the amino acid were involved in the reaction by comparing the changes of the molecular before and after the chelation reaction by infrared spectra,further proved that the product was the amino acid chelate.That the new material,calcium amino acid chelate,was produced was further explained by DSC curve.4.By detecting and analyzing the physical and chemical properties,it was found that self-made calcium amino acid compound was with high purity, good solubility,and the solubility is higher than 10g/100 m L,in the range of 3~9 value p H, which is easy to be absorbed by human body.By comparing the kinds and contents of amino acid from calcium amino acid compound, it was found that there was a good affinity between all kinds of amino acid and calcium ion.Compared with aspartic acid, glutamic acid has stronger chelating ability, however proline is not easy to chelate with calcium because of the heterocyclic structure. |
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