Preparation of mesoporous silica-based nanocomposites with synergistically antibacterial performance from nano-metal (oxide) and polydopamine

In this work, a novel antibacterial nanocomposite system was developed using mesoporous silica (MSN) as an effective nanocarrier, and the resultant nanocomposites demonstrated remarkable antibacterial performance due to the synergistic effect among nano zinc oxides, silver nanoparticles, and polydopamine (PDA). The successful synthesis of MSN/ZnO@PDA/Ag nanocomposites was confirmed. The physicochemical properties and the morphologies of these nanocomposites were investigated. It was found that the particle size increased along with the evolution of these nanocomposites. Besides, nano zinc oxides were formed in the nanoconfinement channel of mesoporous silica with a particle size about 2 nm, and that of silver nanoparticle was less than 50 nm. In addition, the results revealed that the presence of mesoporous silica could effectively prevent the formation of large-size silver nanoparticles and facilitate their well dispersion. Due to the synergistic effect among nano zinc oxides, silver nanoparticles, and polydopamine, these nanocomposites exhibited remarkable antibacterial performance even at a low concentration of 313 ppm, and the antibacterial mechanism was also elucidated. Therefore, this work provides a facile and controllable approach to preparing synergistically antibacterial nanocomposites, and the remarkable antibacterial performance make them suitable for practical applications.

Green Synthesis of Nano Zinc Oxide/Nanohydroxyapatite Composites Using Date Palm Pits Extract and Eggshells: Adsorption and Photocatalytic Degradation of Methylene Blue

In this study, zinc oxide nanoparticles (ZnO) and nanohydroxyapatite (NHAP) were prepared in the presence of date palm pits extract (DPPE) and eggshells, respectively. Another four nanocomposites were prepared from ZnO and NHAP in different ratios (ZP13, ZP14, ZP15, and ZP16). DPPE and all nanomaterials were characterized using GC-MS, zeta potentials, particle size distributions, XRD, TEM, EDX, FTIR, and pHPZC. The characterization techniques confirmed the good distribution of ZnO nanoparticles on the surface of NHAP in the prepared composites. Particles were found to be in the size range of 42.3–66.1 nm. The DPPE analysis confirmed the presence of various natural chemical compounds which act as capping agents for nanoparticles. All the prepared samples were applied in the adsorption and photocatalytic degradation of methylene blue under different conditions. ZP14 exhibited the maximum adsorption capacity (596.1 mg/g) at pH 8, with 1.8 g/L as the adsorbent dosage, after 24 h of shaking time, and the static adsorption kinetic process followed a PSO kinetic model. The photocatalytic activity of ZP14 reached 91% after 100 min of illumination at a lower MB concentration (20 mg/L), at pH 8, using 1.5 g/L as the photocatalyst dosage, at 25 °C. The photocatalytic degradation of MB obeyed the Langmuir–Hinshelwood first-order kinetic model, and the photocatalyst reusability exhibited a slight loss in activity (~4%) after five cycles of application.

The Effect of Nano-Zinc Oxide and Nano-Titanium Dioxide on Inhabitation of Ochratoxin A

The experiment was conducted at the Agricultural Research Office in Baghdad during July 2020 to test the ability of nanomaterials (ZnO and TiO2) to inhibit ochratoxin A, which is produced by a number of microbiology (fungi) including: Aspergillus ochraceus, A. niger, ,A. steynii, A. carbonarius, Pencillume verrucosum and P. nordicum. The standard ochratoxin A, with known concentration, was treated with different concentrations of nanomaterials (20, 40, 60, and 80 ppm) and two different particle sizes of nanoparticles approximately (15 nm) and (70 nm) for each (ZnO) and TiO2; with 16 transactions. Through an examination of the HPLC, the results showed that all transactions led to a noticeable inhibition in the concentration of ochratoxin A, and the highest inhibition rate was for ZnO nanoparticles with particle-size (70 nm) and 80 ppm concentration, where the inhibition rate was 99%. In other hand, the TiO2 nanoparticles with particle-sized (70 nm) and the concentration (80 ppm) were followed by 95%.

Effect of bio-seed priming and nano zinc oxide foliar application on quality and productivity of finger millet + greengram intercropping system

A critical stage of the plant's life cycle is germination and insufficient seedling emergence contributes to the lower productivity of finger millet. Priming improves seedling emergence, reduces stand establishment time, and improves seedling germination. There is a need to develop a new technology like Nanotechnology that can precisely detect and deliver the right amount of nutrients or other inputs to safe crops for the environment and maximising productivity. A field experiment was conducted during Kharif season to evaluate the response of effective farming practice for sole finger millet + greengram intercropping system under rainfed conditions to varied levels of bio-seed priming and foliar application of nanoparticles on crop growth and productivity. The results of the experiment revealed that finger millet (Eleusine coracana) intercropped with greengram (Vigna radiata) (2:1) had a significant level (<0.05) increase in growth and yield parameter of finger millet compared to sole finger millet. Application of Prosopis juliflora leaf extract 1 per cent alone + Foliar ZnO nanoparticle @ 500 ppm showed a significant level (<0.05) increase in growth and yield parameter like grain yield (3238.84 kg ha-1), finger millet equivalent yield (FMEY) (3483.84 kg ha-1) and straw yield (7393.83 kg ha-1) compared to Pogamia pinnata leaf extract 1% alone + Foliar ZnO nanoparticle @ 500 ppm. The present study mainly focussed on cropping system, bio seed priming, and foliar application of nano zinc oxide utilized during rainfed conditions to increase uniform germination, drought resistance and improve crop yield along with nutrient content in seeds.

Effect of Zinc Fortification on Quality, Yield and Economics of Sweetcorn

A field experiment was performed at Agricultural College, Bapatla, ANGRAU, Guntur during kharif season of 2020 to evaluate the efficacy of zinc nutrition on quality, yield and economics of sweetcorn. Experiment was carried out in Randomized Block Design and comprising of nine treatments with three replications. The results disclosed that application of recommended dose of fertilizers along with soil application of 10 kg ha-1 Zn EDTA + two foliar sprays of nano zinc @ 250 ppm at 20 & 40 DAS registered remarkably higher protein content (12.98%) and zinc content (34.59 ppm) in kernel which was considered to be superior over the remaining zinc management practices tried. Also, highest green cob (12,638 kg ha-1), green fodder (19,674 kg ha-1), stover yield (7,590 kg ha-1) and gross returns (₹ 1,93,360 ha-1) was recorded from the treatment with soil application of Zn EDTA @ 10 kg ha-1 + two foliar sprays of nano zinc @ 250 ppm at 20 & 40 DAS along with RDF over control. However, highest net returns (₹ 1,38,664 ha-1) and benefit cost ratio (2.74) was recorded with RDF + ZnSO4 @ 25 kg ha-1 (Soil) + Nano ZnO @ 250 ppm at 20 and 40 DAS (Foliar spray). The effectiveness of Zn EDTA compared to ZnSO4 is responsible for the higher quality parameters and yield of sweetcorn but due to its higher cost, Net returns and B;C ratio are maximum for the plots treated with ZnSO4 making it more economically viable.

Synthesis of nano zinc oxide and its effect on the cure characteristic and properties of natural rubber vulcanizates

In this work, nano ZnO was synthesized by a simple method using a polymeric substance as a dispersing agent. Characterization of the synthesized ZnO by XRD and SEM confirmed the ZnO was nanometric in size and had a wurtzite structure. The synthesized nano ZnO was used as an activator for natural rubber vulcanization. Different amount of ZnO, 1, 2 and 3 phr, was investigated in the rubber formulation and compared to convention ZnO at a typical amount (6 phr). The sample with 3 phr nano ZnO showed the lowest curing induction time with the highest (ML-MH) at all studied temperatures. Furthermore, the rubber sample with 3 phr ZnO achieved the best properties, i.e., crosslink density, rebound resilience, and hardness compared to the rubber sample with 6 phr conventional ZnO. Interestingly, the properties of rubber sample with 2 phr nano ZnO were probably equivalent and comparable to that of 6 phr conventional ZnO. Thus, it suggested that the synthesized nano ZnO could replace the convention ZnO as an activator for rubber vulcanization even at a lower amount.