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 pH_PZC. 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.

Generally, the bioconversion of lignocellulolytics into a new biomolecule is carried out through two or more steps. The current study used one-step bioprocessing of date palm fronds (DPF) into citric acid as a natural product, using a pioneer strain of Trichodermaharzianum (PWN6) that has been selected from six tested isolates based on the highest organic acid (OA) productivity (195.41 µmol/g), with the lowest amount of the released glucose. Trichoderma sp. PWN6 was morphologically and molecularly identified, and the GenBank accession number was MW78912.1. Both definitive screening design (DSD) and artificial neural network (ANN) were applied, for the first time, for modeling the bioconversion process of DPF. Although both models are capable of making accurate predictions, the ANN model outperforms the DSD model in terms of OA production, as ANN is characterized by a higher value of R² (0.963) and validation R² (0.967), and lower values of the RMSE (13.44), MDA (11.06), and SSE (9749.5). Citric acid was the only identified OA as was confirmed by GC-MS and UPLC, with a total of 1.5%. In conclusion, DPF together with T. harzianum PWN6 is considered an excellent new combination for citric acid biosynthesis, after modeling with artificial intelligence procedure.

The removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from waste water was studied by three activated carbon samples (AP21, AZ21 and AN13) prepared from date palm pits (DP) as a precursor and phosphoric acid, zinc chloride and sodium hydroxide as activating agents. Different techniques were used to characterize the solid adsorbents as N₂-adsorption at −196°C, scanning electron microscopy (SEM), thermo gravimetric analysis (TGA) and FT-IR. The effect of various operating parameters such as initial concentration of 2, 4-D, contact time, temperature, adsorbent dosage, and pH were investigated. Equilibrium isotherms were used to identify the possible mechanism of the adsorption process. Characterization results showed that AN13 sample gave the heights surface area 498.9 m²/g and micropores volume 0.239 cm³/g. pH_pzc, pH of the supernatant and FT-IR indicated the presence of different C-O function groups. It was shown that the adsorption of 2, 4-D on activated carbon samples could be best fitted to Langmuir equation with q_m 80 mg/g in case of AN13. The kinetic data were also examined with applying pseudo-first-order and pseudo-second-order kinetics models and was found to follow closely the pseudo-second-order kinetic model. Thermodynamic parameters such as enthalpy changes (Δ H°), entropy changes Δ S° and free energy changes (Δ G°) were evaluated indicating that the nature of adsorption was found to be endothermic and spontaneous.

The survival and growth of in vitro plantlets are still problematic for the date palm; thus, the application of nanotechnology may provide date palm plantlets that develop faster with enhanced growth and biochemical parameters. Moreover, the usage of Fe-modified activated carbon (Fe-AC) prepared from date palm pits instead of activated charcoal (AC) in tissue culture media during the current investigation can be considered an innovative approach. Furthermore, the effect of zinc oxide nanoparticles (ZnO-NPs) and bulk particles (ZnO-BPs) on the rooting and growth of date palm plantlets and on some physiological indices was also investigated. X-ray diffraction, dynamic light scattering, scanning electron microscopy, and transmission electron microscopy were used to characterize Fe-AC and ZnO-NPs. As detected from the characterization, the particle size was 720 nm for Fe-AC and 60 nm for ZnO-NPs. The obtained results indicated that AC significantly enhanced plantlet growth, plantlet height, number of leaves/plantlet, root length, number of roots/plantlet, and the concentrations of IAA, chlorophyll a and chlorophyll b compared with Fe-AC. On the other hand, sugars and phenols concentrations, and POD and PAL activities were highly increased with Fe-AC. There was no significant difference in terms of plant fresh weight (FW), leaf length, leaf width, protein, amino acids, and carotenoids. ZnO nanoparticles significantly improved plant height, leaf length, leaf width, root length, and the concentrations of IAA, chlorophylls a and b, and carotenoids; in contrast, the bulk form increased roots/plantlet, amino acids, and total sugars. Supplying the MS medium with combinations of ZnO-NPs or ZnO-BPs and AC or Fe-AC significantly increased all growth and physiological parameters. Plant height, leaf length, leaf width, root length, and the concentrations of IAA, protein, and chlorophylls a and b significantly increased when ZnO-NPs were combined with AC. Amino acids, total sugars, carotenoids, and phenols concentrations and the activities of POD and PAL increased when ZnO-BPs and Fe-AC were added together.

A field experiments were conducted to evaluate the effects of green synthesis of zinc oxide nanoparticles (ZnO NPs), that prepared in the presence of date palm pits extract (DPPE) through two successive seasons 2018-2019 and 2019-2020 at Agricultural Experimental Research Station of Tag El-Ezz, Agriculture Research Center, Dakahlia Governorate, Egypt, to assay the response of pea plant (Pisum sativum L.) cv. Master-B cultivars to foliar spray by different zinc oxide nanoparticles concentrations (20, 40, 60, 80, 100, 200, 400, 500, 1000 mgl-1) compared with spraying with zinc sulfate 1000 mgl-1as control treatment. The field experiment was carried out in a randomized complete block design with three replicates. The results showed that plants spraying with nano zinc oxide with different concentrations gave various responses compared with those spraying with zinc sulfate. Spraying with 100 mgl-1 was significantly improved the growth attributes of pea plant through two seasons. While treating pea plants with 200 mgl-1 ZnO NPs improved weight of green pods per hectare and weight of 100 seeds during two seasons. Additionally, their positive stimulation for mineral contents, carbohydrates and protein of pea seeds.

Seed germination reflects an important stage of the whole plant life cycle. So, this experiment was conducted to study the effect of five concentrations of composite nano silica/Activated Carbon, sodium silicate (100, 300, 500, 700 and 1000 mgl-1) compared to control to compare their effects on alleviating salt stress during seed germination of fenugreek (Trigonella foenum-graecum. L) under Na+ stress (100 mM NaCl). From results it was illustrated that both of 300 and 500 mg l-1 SiO2/AC induced final germination% by (45%) compared with untreated seeds. While the rate of 300 mg l-1 SiO2/AC significantly increased vigor index, fresh and dry weight of seedlings, and germination index, conversely, it reduced the mean germination time by 56.60%. On other side, root shoot ratio was induced with 500 mg l-1 SiO2/AC by 59.57 comparing with control. It was found that applications of 1SiO2/ AC improve saline tolerance, root , growth efficiency of fenugreek