Improvement of optical and structural properties of ZIF-8 by producing multifunctional Zn/Co bimetallic ZIFs for wastewater treatment from copper ions and dye.

In the paper, high specific surface area (SSA) mono and bimetallic zeolitic imidazolate frameworks (ZIFs) based on zinc and cobalt metals are successfully synthesized at room temperature using different ratios of Zn to Co salts as precursors and ammonium as a solvent to tailor the properties of the produced ZIF and optimize the efficiency of the particles in water treatment from dye and copper ions, simultaneously. The results declare that monometallic and bimetallic ZIF microparticles are formed using ammonium and the tuning of pore sizes and also increasing the SSA by inserting the Co ions in Zn-ZIF particles is accessible. It leads to a significant increase in the thermal stability of bimetallic Zn/Co-ZIF and the appearance of an absorption band in the visible region due to the existence of Co in the bimetallic structures. The bandgap energies of bimetallic ZIFs are close to that of the monometallic Co-ZIF-8, indicating controlling the bandgap by Co ZIF. Furthermore, the ZIFs samples are applied for water treatment from copper ions (10 and 184 ppm) and methylene blue (10 ppm) under visible irradiation and the optimized multifunctional bimetallic Zn/Co ZIF is introduced as an admirable candidate for water treatment even in acidic conditions.

The physical properties and photocatalytic activities of green synthesized ZnO nanostructures using different ginger extract concentrations.

The green synthesis method which is aligned with the sustainable development goals (SDGs) theory, is proposed to synthesize ZnO nanoparticles using ginger extract to treat the acidic wastewater and acidic factory effluent as a current challenge and the effects of the concentration of extracts on the synthesized ZnO nanostructures are investigated. The results declare that the single-phase hexagonal ZnO is formed using ginger extract concentration of less than 25 mL and the crystallite size of green synthesized ZnO NPs increased with increasing the concentration of ginger extract. Also, the significant effects of ginger extract concentration on the morphology of nanoparticles (nanocone, nanoflakes, and flower-like) and the particle size are demonstrated. The low concentration of ginger extract leads to the formation of the ZnO nanoflakes, while the flower-like structure is gradually completed by increasing the concentration of the ginger extract. Furthermore, significant changes in the specific surface area (SSA) of the samples are observed (in the range of 6.1-27.7 m2/g) by the variation of ginger extract concentration and the best SSA is related to using 10 mL ginger extract. Also, the strong effect of using ginger extract on the reflectance spectra of the green synthesized ZnO NPs, especially in the UV region is proved. The indirect (direct) band gap energies of the ZnO samples are obtained in the range of 3.09-3.20 eV (3.32-3.38 eV). Furthermore, the photocatalytic activities of the samples for the degradation of methylene blue indicate the impressive effect of ginger extract concentration on the degradation efficiency of ZnO nanoparticles and it reaches up to 44% and 83% for ZnO NPs prepared using 5 mL ginger extract in a pH of 4.3 and 5.6, respectively. This study provided new insights into the fabrication and practical application of high-performance ZnO photocatalysts synthesized using ginger extract in degrading organic pollutants in an acidic solution.

Highly sensitive asymmetric and symmetric cancer sensors with ultra-high-quality factor and resolution power.

In the paper, we proposed two new highly sensitive and compact biosensors with ultra-high-quality factors based on the 1-D binary photonic crystal (silicon/air thin layer) with a defect layer. The proposed asymmetric and symmetric biosensors have just a few periods (two to five) on both sides of the defect layer and the normal cell group (INOK) and cancer cells group (YD-10B) are considered for the studies. The effects of different parameters including silicon layer thickness, air layer thickness, defect layer thickness, substrate position, number of periods, and light incident angle are considered in the biosensor operation and the biosensors are optimized based on the sensitivity. The results demonstrate that the sensitivity and defect mode wavelength of the sensors are independent of the substrate position. However, the quality factor and FOM of the sensors significantly depend on the substrate position and they are improved significantly in the symmetric sensor (~ 37% improvement in optimum condition). Also, the high sensitivities of the sensors are maintained over a wide range of silicon and air thicknesses, which is a valuable achievement in the manufacturing process. Furthermore, the sensitivity of the optimized biosensors with a defect layer thickness of 10 microns and only two periods reaches S ~ 2811 nm/RIU which is an excellent sensitivity for an optical biosensor.

High specific surface area γ-Al2O3 nanoparticles synthesized by facile and low-cost co-precipitation method.

Alumina (Al2O3) nanoparticles (NPs) are particularly adsorbent NPs with a high specific surface area (SSA) that may well be utilized to clean water. In this study, pure γ-alumina NPs are successfully synthesized by the co-precipitation method, and the effect of ammonium bicarbonate concentration on the synthesized NPs is studied to find the optimum concentration to provide the highest capacity of copper ions removal from water. The results declare that spherical alumina NPs with average diameters in the range of 19-23 nm are formed with different concentrations of precipitation agent, and the concentration has no significant effect on the morphology of NPs. Furthermore, the precipitating agent concentration influences the optical characteristics of the produced alumina NPs, and the bandgap energies of the samples vary between 4.24 and 5.05 eV. The most important impact of precipitating agent concentrations reflects in their SSA and capacity for copper ion removal Ultra-high SSA = 317 m2/g, and the highest copper removal at the adsorbate concentration of 184 mg/L is achieved in an alkalis solution followed by a neutral solution. However, admirable copper removal of 98.2% is even achieved in acidic solutions with 0.9 g/L of the alumina NPs synthesized at a given concentration of ammonium bicarbonate, so this sample can be a good candidate for Cu ions removal from acidic wastewater.