4 research outputs found
Numerical verification of delta shock waves for pressureless gas dynamics
AbstractThe subject of this paper is theoretical analysis and numerical verification of delta shock wave existence for pressureless gas dynamic system. The existence of overcompressive delta shock wave solution in the framework of Colombeau generalized functions is proved. This result is verified numerically by specially designed procedure that is based on wave propagation method implemented in CLAWPACK. The method is coupled with dynamic refinement mesh. We also consider a strictly hyperbolic system obtained from the original one by perturbation and change of variables. The same numerical procedure is applied to the perturbed problem. The obtained numerical results in both cases confirm theoretical expectations
New life of waste material: immobilized horseradish peroxidase for degradation of antraquinone dye
Various strategies have been developed for the removal of synthetic dyes from the
wastewater of the textile industry due to their stability as well as their negative effect on the
environment. Enzymatic wastewater treatments as environmentally safe processes have many
benefits. An enzyme suitable for use in the treatment of wastewater from the textile industry
is horseradish peroxidase (HRP) because it can degrade different types of dyes. Immobilized
enzymes have many advantages over free enzymes in solution such as higher stability and the
opportunity to be removed easily from the reaction mixtures. Consequently, immobilized
enzymes can be used more than once. Many different materials are used as a carrier for
enzyme immobilization, so if residual material is used as a carrier, waste valorization will be
achieved. In this study immobilized commercial HRP was used for decolorization of
anthraquinone dye Acid green 40 (AG 40). Waste material – potato peels were used as a
carrier for the immobilization of HRP. Potato peels were oxidized with sodium periodate to
introduce aldehyde groups that can react with the primary amino groups of the enzyme to
form Schiff bases, resulting in covalently immobilized HRP. The success of the oxidation
was verified by the 2,4-dinitrophenylhydrazine (DNPH) test, and subsequently, the oxidized
potato peels were characterized by SEM and FTIR. After oxidation, the influence of the mass
of the immobilization carrier on enzyme activity and immobilization efficiency was
investigated. The optimal conditions of pH, hydrogen peroxide concentration, concentration
of AG 40, and enzyme activity were determined for decolorization of AG 40 with
immobilized HRP. Adsorption of AG 40 on the carrier was also determined. In addition, the
operational stability of the enzyme was determined. The results obtained show that oxidized
potato peels are a promising material that can be used as a carrier for the immobilization of
HRP
Postupak za imobilizaciju enzima na oksidovanim ljuskama krompira
Patentna prijava P-2023/1067.
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