Adsorption of Rose Bengal dye from waste water onto modified biomass.

Herein, adsorption of Rose Bengal dye (RB) from aqueous solution was investigated. Nano raw orange peel (OP) activated carbon (AC) coated with nano chitosan (Cs) to obtain nano chitosan/activated carbon (AC/Cs) composite which cross-linked with functionalized multi-walled carbon nanotubes (MWCNTs-COOH) to create a novel composite (AC/Cs/MWCNTs) with high surface area (1923 m2/g). The examined parameters such as concentration (1-7 ppm), pH (6.5-9.5) and temperature (295-323 K) were traversed. The maximum removal efficiency was at pH 6.5, increased from 70.4% for nano OP to 94.7% for AC/Cs/MWCNTs nano composite. Langmuir isotherm model was the best fitting to acquired data (R2 ≥ 0.99). Also, the adsorption of RB matched with pseudo-second order model, t0.5 results for pseudo-second order was 4.4672 for nano OP and 1.2813 for AC/Cs/MWCNTs at 303 K. Thermodynamic studies showed that the adsorption of RB dye is exothermic and spontaneous due to the negative value of ΔG and ΔH.

Enhancement of photocatalytic and biological activities of chitosan/activated carbon incorporated with TiO2 nanoparticles.

Novel and sustainable chitosan (CS)/activated charcoal (AC) composites were prepared by cross-linking with epichlorohydrin (ECH) to form a porous structure. Different titanium dioxide nanoparticle (TiO2 NPs) concentrations (0, 0.2, 0.4, and 0.8% w/w) were added to enhance the photocatalytic, antibacterial, larvicidal, and pupicidal activities' efficiency toward Rose Bengal (RB) dye and the Culex pipiens. The composites were characterized by FT-IR, XRD, XPS, BET and SEM. The SEM images revealed the porous structure of CS/AC and TiO2 nanoparticles were uniformly distributed in the CS/AC matrix. The degradation of RB dye was used to test the photocatalytic behavior of the composites. Supporting TiO2 on a CS/AC matrix resulted in a significant increase in photocatalytic performance. The antibacterial activities supported by CS/AC/TiO2 NPs were evaluated by bacterial growth inhibition against B. subtilis, S. aureus, E. coli, and P. aeruginosa. The results showed that CS/AC/TiO2 NPs composite has an inhibitory effect and therefore considered antibacterial agents. CS/AC/0.4%TiO2 NPs showed maximum efficacy against larvicidal activity and pupicidal of mosquito vector which recorded 99.00 ± 1.14, 95.00 ± 1.43, and 92.20 ± 2.64 for the first, second, and third larval instars and 66.00 ± 2.39 for pupal mortality, while the repellent activity reported high protection at 82.95 ± 2.99 with 3.24 mg/cm2 dose compared to control DEET.

Multifunctional cellulose nanocrystal /metal oxide hybrid, photo-degradation, antibacterial and larvicidal activities.

Cellulose nanocrystal (CNC) and ZnO/CuO nanostructure were successfully synthesized by acid hydrolysis and sol-chemical methods, respectively. For the first time, CNC was used as a host polymer for synthesis of CNC/ZnO/CuO through In-situ solution casting technique. Morphological and structural of CNC, ZnO/CuO and hybrid CNC/ZnO/CuO were investigated by TEM, SEM-EDX, FT-IR, XRD and XPS analyses. The analysis revealed that, poly-dispersed, smooth and rod like CNC with an average length of ∼ 85.4 nm, average diameter of ∼13.9 nm and surface charge of 0.01 mmol/gm. As well, irregular shapes as hexagonal, spherical and cluster or star like of ZnO/CuO were formed. EDX and XRD spectra exhibited highly purified CNC/ZnO/CuO and pointed to cellulose II crystallite form with a monoclinic structure. The results demonstrated that, 91.3 % and 99.7 % dye degradation was achieved after 40 min of irradiation due to ZnO/CuO and CNC/ZnO/CuO treatment. Moreover, the inhibition zones formed due to 100 ppm ZnO/CuO were duplicated after integrating CNC (from 7.7:10.3 mm to 14.3:20.3 mm). The hybrid nanostructure exhibit larvicidal activity against Anopheles stephensi better than CNC and ZnO/CuO nanostructures.