Papers by Keyword: Immobilisation

Abstract: Photosensitizers immobilized in polymers can serve as antibacterial surfaces or coatings and can be applied for disinfection of water or medical instruments. The antibacterial activity of the immobilized photosensitizers is based on their excitation by visible light followed by energy transfer from the photosensitizers to oxygen dissolved in an aqueous phase which produces reactive oxygen species that cause irreversible damage to bacterial cells. The photosensitizer Rose Bengal immobilized in polystyrene, polycarbonate and poly (methyl methacrylate) was shown to eradicate Gram-positive Staphylococcus aureus bacteria under moderate illumination.

Abstract: AOD slag samples from steel works of Outokumpu Stainless Company were used to study F-dissolution relating to treatments for volume stabilization. Results from the slag tests and sample characterizations indicate that the slag re-melting with or without reduction and granulation with either water or gas have rather small effects on F leaching, as well as formation of different C₂S polymorphs. The chemical composition and cooling condition are the two important parameters to control F leaching from slag samples. These two parameters should be combined together in an optimum way by the steel industry to treat slags for F-immobilization.

Abstract: Reduction and immobilization of Cr (VI) as Cr₂O₇^2- is investigated by using metakaolinite-based geopolymer complexed reductant. Without reductants, the leached Cr concentration from metakaolinite-based geopolymer containing Cr (VI) is very high. Adding reductants as FeCl₂·4H₂O, FeSO₄·7H₂O, and Na₂S·9H₂O respectively during geopolymerization, the leached Cr concentration is below 5 mg L^-1 with high Cr immobilization rate above 99 %. By comparison with the immobilization of Cr (III), the added reductants reduced Cr (VI) to Cr (III) which can be locked successfully in the amorphous structure of geopolymer. Meanwhile, Cr (VI) initial concentration is lower than 0.7 wt. % in metakaolinite-based geopolymer, the above reductants can all meet the requirements. While for Cr (VI) initial concentration larger than 0.7 wt. %, Na₂S·9H₂O is more appropriate. Such a simultaneous reduction and immoboilization process enables the feasibility of using metakaolinite-based geopolymer complexed reductant to implement a one-step procedure for chromite ore processing residue cleanup.

Abstract: Aiming to apply in removal of selenium from contaminated waste water, we have studied the immobilization of Se (IV) and Se (VI) into the hydrate of calcium alumino-zincate (14CaO.5Al₂O₃.6ZnO, shown as C₁₄A₅Z₆). By adding 2 g of C₁₄A₅Z₆ to 1 L of 5 mg/L Se (VI) solution, the concentration of Se (VI) was decreased to less than 0.01 mg/L within 60 minutes. In the case of using 1 g of calcium hydroxide with 2 g of C₁₄A₅Z₆, the Se (VI) concentration reached to 0.01 mg/L within 30 minutes. On the other hand, the concentration of Se (IV) was decreased from 5 mg/L to 0.16 mg/L in 60 minutes whilst it reached to 0.041 mg/L by adding calcium hydroxide in the same reaction period. The immobilization capacity of selenium were 222 and 127 mg/g for Se (IV) and Se (VI), respectively. By adding calcium hydroxide, the immobilization capacity of C₁₄A₅Z₆ was increased to 240 and 200 mg/g for Se (IV) and Se (VI), respectively.

Abstract: The purpose of this review is to aim a summary of the development in the use of different supports for the immobilisation of a heterogeneous Fenton catalyst, which areiron-containing materials. Various anchors and immobilisation methods that are universally employed to the remediation of wastewater are considered. Commonly, the immobilisation of a heterogeneous Fenton catalyst onto supportive material has chiefly been approved through one of two major routes; chemical route physical route or physical route. The advantages and disadvantages of various immobilisation methods to obtain a gigantic surface area iron-containing materials support is considered too.

Abstract: To form microbial nanoball, EM active calcium was immobilized on nano-silica carrier consisting of pond sediment, zeolite powder and nanosilica. Through real-time monitoring of pH, dissolved oxygen (DO), chemical oxygen demand (COD) and ammonia nitrogen (NH₄⁺-N) aquaculture wastewater, the purification effects of Microbial nanoSilica Ball on aquaculture wastewater under different mud-water ratio condition were studied. The results showed that the purification effect reached best in 3-6 days for all treatments and was better for mud-water ratio of 1:2.7. In this mud-water ratio, it was indicated that pH was maintained at 7-8.5 which was an optimum value for the aquaculture, the content of DO was increased by 82.16% compared with the initial value and the removal rate of COD and NH₄⁺-N was 57.80% and 54.60% respectively.

Abstract: Functionalized magnetic silica nanospheres were prepared by hydrolyzation of tetraethyl orthosilicate (TEOS) on Fe₃O₄ and modification of Fe₃O₄/SiO_x. Structure of functionalized magnetic silica nanospheres were characterized by transform infrared spectroscopy (FTIR) and differential thermal analysis (DTA). Cellulase was immobilized on functionalized magnetic silica nanospheres through cross-linking method. Saccharification rate of the immobilized cellulase is 70 % of that of free cellulase. The saccharification of the immobilized enzymes after 8 continuous uses still have 10 % of the initial saccharification rate, which demonstrate the potential of this immobilized cellulase for biofuel production.

Abstract: In this paper, Tessier sequence extract procedure (SEP), toxicity leaching procedure (TCLP) and simple bioaccessibility extraction test (SBET) were employed to evaluate the immobile efficiencies for As, Cu and Pb contaminated soils. Experimental results indicated that the TCLP was efficient to extract the most active part heavy metal and evaluate the risk of the samples; the Tessier method divided heavy metals in soils to different fractions. Monitoring the changes of different fractions during the immobilizing procedure could help fully understand the mechanism of stabilization. The SBET method simulated the human digest system, thus it could be used to evaluate the risk changes to human during the immobilizing process; and to reveal the potential risk of chemical stability. In our project, these three evaluate method should be utilized properly to help accessing the risk, electing suitable immobilizing method and evaluating the efficiency of stabilization.

Abstract: This research is focused on the synthesis of a polystiren layer for biosensors based on a Quartz Crystal Microbalance sensor (QCM) to immobilize the biomolecule. The polystyrene thin film was deposited by means of spin coating method with various solvents, such as chloroform, toluene, xylene, and tetrahydrofuran (THF), containing a 3% polystyrene solution by mass. The morphologies of the polystyrene layers were observed via SEM/EDx. The polystyrene surface coated using chloroform as the solvent has a rougher morphology and the largest diameter pores compared with the other solvents. The result show the polystyrene surface coating produced with chloroform caused a higher frequency change, which resulted in the binding of a wider range of biomolecules.

Abstract: Objective To obtain immobilized alpha-glucosidase with good biological activity and improve the utilization rate of alpha-glucosidase. Methods Prepare the core-shell microparticles consisting of poly (methyl methacrylate) (PMMA) cores surrounded by various of chitosan shells, induced by tert-butylhydroperoxide (TBHP). Then fixed the alpha-glucosides N-terminal onto the carriers and studied the optimum immobilization conditions and the property of alpha-glucosidase immobilized.Result Immobilized α-glucosidase enzyme pH stability was higher than the free. In particular, the relative enzyme activity were maintained at 80% in the range of pH4.5 ~ 6.5. Immobilized α-glucosidase optimum temperature is 60 °C, the optimum temperature of the free enzyme is 50 °C. Conclution These Alpha-glucosidase Immobilization can be used as biopolymer and biomaterials in the pharmaceutical and medical application fields.