Water desalination and wastewater treatment via solar photothermal energy conversion are among the most important technologies to address the increasing pressing global water scarcity. Solar energy is the cleanest, most abundant, renewable natural resource available. Herein, we report the development of highly efficient, flexible, low weight, and cost effective Plasmonic Functionalized Cotton (PFC) nanocomposite materials for solar steam generation through the efficient evaporation of surface water pools. The PFC nanocomposites contain metallic nanoparticles that exhibit strong solar absorption followed by non-radiative relaxation causing the absorbed energy to be converted into heat for efficient water evaporation. The chemically modified cotton leads to a partial hydrophobic surface that allows the material to float on the water's surface and provide excellent thermal insulation properties in addition to facile and scalable synthesis. The PFC nanocomposites containing Au and Ag nanoparticles are demonstrated to be among the most efficient solar thermal converters reported to date for solar water desalination. The Au/Ag-PFC fibers exhibit average water evaporation rates of 1.4 and 11.3 kg m⁻² h⁻¹ with superb solar thermal efficiencies of up to 86.3% and 94.3% under 1 and 8 sun illumination, respectively. Furthermore, the Au/Ag-PFC fibers display stable evaporation rates over more than 10 repeated evaporation cycles without any performance decline under acidic solution at pH 2 or basic solution at pH 10. The successful application of the Au/Ag-PFC fibers for the removal of organic dyes from contaminated water through the solar steam generation is also demonstrated. The high solar thermal evaporation efficiency, excellent stability and long-time durability make the PFC nanocomposites excellent candidates for applications in seawater desalination and wastewater treatment by solar-steam generation.

Manganese, zinc, and iron are the most essential micronutrients required for plant growth and applied as foliar fertilizers. Herein, a simple template-free microwave-assisted hydrothermal green synthesis technique was adapted to produce manganese zinc ferrite nanoparticles (Mn0.5Zn0.5Fe2O4 NPs) at different temperatures (100, 120, 140, 160 and 180 °C). The prepared nanomaterials were employed at different concentrations (0, 10, 20, and 30 ppm) as foliar nanofertilizers during the squash (Cucurbita pepo L) planting process. X-ray diffraction patterns of the prepared nanomaterials confirmed successful production of the nanoferrite material. The prepared nanofertilizers showed type IV adsorption isotherm characteristic for mesoporous materials. FE-SEM and HR-TEM imaging showed that the nanoparticles were cubic shaped and increased in particle size with the increase in microwave temperature during production. The impact of application of the synthesized ferrite nanoparticles on vegetative growth, proximate analysis, minerals content and the yield of squash plant was investigated for two consecutive successful planting seasons. The nanoferrite synthesized at 160 °C and applied to the growing plants at a concentration of 10 ppm gave the highest increase in % yield (49.3 and 52.9%) compared to the untreated squash for the two consecutive seasons, whereas the maximum organic matter content (73.0 and 72.5%) and total energy (260 and 258.3 kcal/g) in squash leaves were obtained in plants treated with 30 ppm ferrite nanoparticles synthesized at 180 °C. On the other hand, the maximum organic matter content (76.6 and 76.3%) and total energy (253.6 and 250.3 kcal/g) in squash fruits were attained with plants supplied by 20 ppm ferrite nanoparticles synthesized at 160 °C. These results indicate that the simple template-free microwave-assisted hydrothermal green synthesis technique for the production of manganese zinc ferrite nanoparticles yields nanoparticles appropriate for use as fertilizer for Cucurbita pepo L.

In this research, CuFe₂O₄ nanoparticles were synthesized by co-precipitation methods and modified by coating with thiophene for removal of Hg(II) ions from aqueous solution. CuFe₂O₄ nanoparticles, with and without thiophene, were characterized by x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy dispersive x-ray (EDX), high-resolution transmission electron microscopy (HRTEM) and Brunauer–Emmett–Teller (BET). Contact time, adsorbent dose, solution pH, adsorption kinetics, adsorption isotherm and recyclability were studied. The maximum adsorption capacity towards Hg²⁺ ions was 7.53 and 208.77 mg/g for CuFe₂O₄ and CuFe₂O₄@Polythiophene composite, respectively. Modification of CuFe₂O₄ nanoparticles with thiophene revealed an enhanced adsorption towards Hg²⁺ removal more than CuFe₂O₄ nanoparticles. The promising adsorption performance of Hg²⁺ ions by CuFe₂O₄@Polythiophene composite generates from soft acid–soft base strong interaction between sulfur group of thiophene and Hg(II) ions. Furthermore, CuFe₂O₄@Polythiophene composite has both high stability and reusability due to its removal efficiency, has no significant decrease after five adsorption–desorption cycles and can be easily removed from aqueous solution by external magnetic field after adsorption experiments took place. Therefore, CuFe₂O₄@Polythiophene composite is applicable for removal Hg(II) ions from aqueous solution and may be suitable for removal other heavy metals.

Copper ferrite nano-particles (CuFe₂O₄) were synthesized, characterized, modified with polyaniline to form CuFe₂O₄/PANI nano-composite. They were used as new adsorbents for the removal of the hazardous mercuric ions from aqueous solutions. High resolution transmission electron microscope (HR-TEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) and Brunauer–Emmett–Teller (BET) were used for the characterization of the synthesized CuFe₂O₄ nano-particles (NPs) in presence and absence of PANI nano-composite. The synthesized CuFe₂O₄NPs were of spherical shape with an average size of 10.8 nm. XRD analysis displayed crystal peaks for CuFe₂O₄NPs and amorphous peaks CuFe₂O₄/PANI nano-composite due to the existence of polyaniline layer. Contact time, adsorbent dose, solution pH, adsorption kinetics, adsorption isotherm and recyclability were studied. The method at the optimum conditions exhibited high performance with high mercury removal percentage of up to 99% with a maximum adsorption capacity 12.5 and 157.1 mg/g for CuFe₂O₄ and CuFe₂O₄/PANI, respectively. The adsorption processes were fitted to Langmuir isotherms. The adsorption behavior of CuFe₂O₄@PANI composite towards Hg²⁺ ions is attributed to the soft acid–soft base strong interaction between PANI and Hg(II) ions. High stability and enhanced re-usability are offered using CuFe₂O₄@PANI composite due to its enhanced removal efficiency. No significant removal decrease was noticed after five adsorption–desorption cycles. In addition, it possesses an easy removal from aqueous solutions by external magnetic field after adsorption experiments. These indicated the enhancement of polyaniline to the surface of CuFe₂O₄ toward the adsorption of mercury from aqueous solutions.