Abstract: A direct polycondensation method for medical biodegradable polylactic acid (PLA). The invention uses commercialized creatinine (a type of biomaterial organic guanidine compounds—the arginine metabolite creatinine in human body) as the catalyst and industrial lactic acid (mass content 85-90%, aqueous solution) as the monomer to synthesize the PLA in terms of second polycondensation without solvent. Instead of tin catalysts having cytotoxicity, the catalyst used in the invention has high biocompatibility and biosafety. The synthesized PLA does not contain any metal and other toxic components; therefore, it can be used as the carrier for targeting drugs and controlled release drugs. The green catalyst and green processing method (no solvent applied and no toxic products produced) are used to synthesize the green biodegradable PLA with high biosafety. The molecular weight distribution for all synthesized products is narrow and the molecular weight is controllable within 1.5-3.0×104.

Abstract: A method for synthesizing a medical grade biodegradable material, poly(lactic-co-glycolic acid), copolycondensation of lactic acid and glycolic acid catalyzed by biomass creatinine. The present invention uses commercialized creatinine (a type of biomaterial organic guanidine compounds—the arginine metabolite creatinine (CR) in human body) as the catalyst and industrial lactic acid (LA, mass content 85%, aqueous solution) and glycolic acid (GA, 95%) as the monomer to synthesize the high biosafety of medical poly(lactic-co-glycolic acid) in terms of two steps polycondensation without solvent.

Abstract: Disclosed is a high molecular weight polylactic acid synthesized by using a method for synthesizing and catalytically-polycondensing bionic creatinine-guanidinium chloride. Creatinine is used as the material in a reaction with aqueous hydrochloric acid to synthesize a bionic creatinine-guanidinium salt catalyst, creatinine-guanidinium chloride (CR.Cl). The creatinine-guanidinium chloride synthesized is used as a catalyst, an industrial grade lactic acid (LA, 85% to 90%, aqueous solution) is used as a monomer, a solvent-free two-step polycondensation method is used to synthesize and afford metal-free and toxic residue-free polylactic acid featuring high biological safety and high molecular weight.

Abstract: A method for regulating the distribution of metallic nanoparticles within the resin support is provided. This method uses the ion exchange or absorption resin bearing basic functional groups as the support; firstly introducing the metal in the form of anionic complexes onto the resin support through the ion exchange process, then realizing the purpose of regulating the distribution of the metal and its compound within the resin support by means of changing the concentration of the reductive or deposition agent in water solution and the reaction time. The regulated distribution of metallic nanoparticles within the resin support is in the form of rings with different depths and densities.

Abstract: The present invention provides a direct polycondensation method for medical biodegradable polylactic acid (PLA) using creatinine catalyzed lactic acid. The invention uses commercialized creatinine (a type of biomaterial organic guanidine compounds—the arginine metabolite creatinine (CR) in human body) as the catalyst and industrial lactic acid (LA, mass content 85-90%, aqueous solution) as the monomer to synthesize the high biosafety of medical PLA in terms of second polycondensation without solvent (identity). Instead of tin catalysts having cytotoxicity, the catalyst used in the invention has high biocompatibility and biosafety. The synthesized PLA does not contain any metal and other toxic components; therefore, it can be used as the carrier for targeting drugs and controlled release drugs. In addition, the green catalyst and green processing method (no solvent applied and no toxic products produced) are used in the invention to synthesize the green biodegradable PLA with high biosafety.

Abstract: The invention discloses a novel method for trace phosphate removal from water by using a composite resin. Firstly, adjusting the pH value of the raw water to 5.0˜9.0 and prefiltering the water, then leading the filtrate through an absorption tower packed with the composite resin, the trace phosphate in the water is therefore absorbed onto the composite resin; stopping the absorption run when it reaches the leakage point, using a binary NaOH-NaCl solution as the regenerant of the exhausted sorbent, followed by rinsing the composite resin-filled absorption tower with saturated carbon dioxide solution to regenerate the resin. In this invention, a composite resin with nanosized hydrated ferric oxide (HFO) or hydrous manganese dioxide (HMO) particles loaded on its surface is adopted as the absorbent for enhanced phosphate removal from water. A significant decrease of phosphate content in the effluent from this treatment system is found from 0.