283 publications from this institution
In this paper, the Laccase enzyme was covalently immobilized onto nanoparticle of zeolite (NZ)-graphene oxide (GO) composites to prepare the novel nanobiocatalysts for degrading Direct Red 23 as an organic pollutant. Graphene oxide-zeolite (GZ) nanocomposites with 0.03, 0.05, and 0.07 g amounts of GO (denoted as GZ3, GZ5, and GZ7, respectively) were synthesized. The materials were silanized for synthesizing SNZ, SGZ3, SGZ5, and SGZ7. The glutaraldehyde as a cross-linking agent was used to prepare GSNZ, GSGZ3, GSGZ5, and GSGZ7. Laccase was immobilized on them for synthesizing Laccase immobilized nanobiocatalysts including LIGSNZ, LIGSGZ3, LIGSGZ5, and LIGSGZ7. The SEM, FESEM, XRD, FTIR, TEM, HPLC, and UV–vis were used for characterizing materials and dye degradation. The effects of GO ratio, catalyst dosage, dye concentration and pH on pollutant biodegradation were evaluated and optimized. The nanobiocatalysts indicated well reusability over five cycles, high storage stability, and thermal stability.
A new method for preparing geopolymer filtrations was suggested, using silica fume in an alkali activator as an environmentally and economically sustainable material. The geopolymer filtration was fabricated by activating metakaolin with a blend of sodium hydroxide and silica fume. Different phase structures and microstructures were fabricated with varying preparation parameters, such as silica fume content, Na2O/Al2O3 molar ratios, and curing temperatures. The filters were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersion spectroscopy, and mercury intrusion porosimetry. Filters were tested for pure water flux, compressive strength, and wastewater permeability using industrial textile wastewater. The geopolymer-zeolite composite filter, including 10 wt% silica fume, Na2O/Al2O3 molar ratio of 1, and curing temperature of 60 °C exhibited the highest pure water permeability of 144 L/m2.h.bar, wastewater permeability of 77 L/m2.h.bar, and achieved 95.5 % turbidity reduction for the textile wastewater.
