This paper reports on the manufacture of ZnO nanoparticles (ZnO NPs) from Prosopis juliflora leaf extracts. Various methods of characterization were used, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and transmission electron microscope TEM. ZnO NPs has a hexagonal wurtzite structure with a preferred orientation of 101 planes, according to XRD. The functional groups found in ZnO NPs isolated from leaves are responsible for the FT-IR peaks that correspond to them. The morphology of the produced nanoparticles is a sphere-like form, as shown in the SEM pictures. TEM examination revealed ZnO NPs with a size of 50–55 nm. These ZnO NPs were used to remediate pollutants in paper mill effluents, and they were able to remove 86% of the organic pollutants from the sample at 0.05 mg/L dose and reduce 89% of the organic pollutants during a 5-h reflex time. Meanwhile, for the photocatalysis of paper mill effluents, it has been noted that COD was removed by 74.30%, 63.23%, and 57.96% for the first, second, and third cycles, respectively.

The wild vegetation of the Eastern Desert is characterized by openness and comprises perennials and ephemerals. The current study investigated the relationship between the edaphic factors of the natural vegetation along El Sheikh Fadl–Ras Gharib Road, Southwest Suez Gulf, in the northern sector of the Eastern Desert. The vegetation structure of the study area is relatively simple. The surveyed plants included 93 species from 22 families (51 perennials and 42 annuals). Asteraceae, Brassicaceae, Amaranthaceae, and Fabaceae were the richest families, constituting the majority of plant species (53.76%). Therophytes were the most frequent life forms. About 83.87% of the total flora were pluriregional elements of different affinities. Most of the recorded taxa occupied the Irano-Turanian/Mediterranean/Saharo-Sindian/Sudano-Zambezian chorotypes. The application of TWINSPAN classification resulted in grouping the vegetation into three main vegetation groups (A, B, and C), representing distinct microhabitats. The CCA ordination indicates diversity in vegetation group A. Group B was highly associated with Na, Mg, CaCO₃, silt, clay, and C/N. Group C showed a high correlation with sand, K, and N. The differences in wild plant life forms, richness, and diversity along the studied desert roadsides, in association with the soil differences, provide a good indication of plant biodiversity.

Sustainable ecological agriculture is achieved by regulating the benefits of trees. The application of leguminous trees as alley cropping protects and increases soil fertility, improves the quality of water by intercepting pesticides, changes the local climate, improves biodiversity, and thus improves productivity. In order to evaluate the impact of alley cropping upon the growth and productivity attributes of fennel, an experiment was carried out during two seasons. The experiment included eight treatments. Fennel seeds were cultivated between Sesbania alleys and treated with N and endophytic fungi according to the eight treatments. After harvesting the fennel, different parameters were determined and biochemical analyses were conducted. All of the alley cropping treatments showed remarkable superiority in all measures of fennel growth and productivity compared to the sole crop treatment. Among the different alley cropping treatments, applying Sesbania at 4 m spacing with N fertilizer and EF increased most of the studied parameters in terms of the least number of days from planting until harvesting of fennel, herb dry weight, number of umbels, fruit yield, essential oil, N, P, and K content, and pigments. In contrast, the highest plant height was recorded with fennel–Sesbania at 2 m spacing + N fertilizer + EF. Applying fennel–Sesbania at 6 m spacing + N fertilizer + EF treatment resulted in higher stem diameter and increased the number of main branches compared to the other treatments.

Natural habitats in littoral salt marshes and desert salt marshes along the coastline of the Red Sea are inhabited by several halophytes, which tolerate salinity stress in these areas. Two distinct halophytes inhabiting the Red Sea coast, Limonium axillare and Nitraria retusa, were studied for their physiological adaptations and energy sources. Results revealed the accumulation of the most abundant soil salts in their tissues. The soils in the study area recorded high concentrations of Na+ and Cl- compared with other ions such as Ca2+, Mg2+, and K+. To combat this stress, the two species absorb salts to adjust the osmotic potential and raise the concentrations of soluble organic compounds – such as proline, soluble sugars, and nitrogen components – in their leaves. In anaerobic digestion, both species yield a large amount of organic components that might act as a source for the production of biogas. L. axillare produced more biogas 277.58 ml g-1 TS (361.23 ml g-1 VS) compared with N. retusa which produced 204.2 ml g-1 TS (309.4 ml g-1 VS). The presence of soluble organic solutes represents easily breakable molecules in anaerobic digestion. Therefore, L. axillare produced more biogas with more soluble carbohydrates (22.15 mg g-1 dry wt), proline (13.47 mg g-1 dry wt), and soluble protein (33.06 mg g-1 dry wt) compared with N. retusa which contains less soluble carbohydrates (18.53 ml g-1 dry wt), proline (13.64 mg g-1 dry wt), and soluble protein (20.04 mg g-1 dry wt).

Surface water quality and the seasonal dynamics of the Nile River in the Aswan district were analyzed using multivariate data analysis and overall pollution index (OPI) analysis. Water samples were collected from four sampling sites, including a reference site (site 1) and three sites receiving effluents from different pollution sources, e.g., domestic-like pollutants (site 2), industrial (site 3), and agricultural effluents (site 4). Different water quality parameters, such as physicochemical characteristics and nutrient minerals, were analyzed in the selected sites. The average OPI values were calculated by classifying the surface water quality of each site as follows: at site 1 (1.65: excellent), site 2 (2.70: acceptable), site 3 (11.75: polluted), and site 4 (5.08: slightly polluted). In each site, the OPI values varied seasonally within the range of water quality class, except, in autumn at site 4, the OPI value was 10.00, and hence the water quality class was changed to (polluted). Generally, it was concluded that the industrial effluents had an adverse effect on the surface water quality of the Nile River, Aswan. Consequently, special concerns should be assumed to maintain environmental sustainability.