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Acacia honey is characterized by high nutritional, antioxidant, antibacterial and immuno-modulatory values. This work investigated the presence of short and cyclic peptides in Acacia and Ziziphus honey samples. Acacia honey samples (Acacia tortilis and Acacia hamulosa) and three Ziziphus honeys (Ziziphus spina-christi) were screened for their short and cyclic peptide contents using the LC-MS and the chemical structure databases. Moreover, the total protein content was determined using the Bradford method. The A. tortilis honey contained three short peptides; HWCC, DSST, and ECH, and the A. hamulosa honey sample contained five short peptides and one cyclic peptide. The short peptides of the A. hamulosa honey were Ac-GMGHG-OH (Ac-MGGHG-OH), Boc-R(Aloc)2-C(Pal)-OH, H-C (1)-NEt2·H-C (1)-NEt2, APAP (AAPP), and GAFQ (deamino-2-pyrid-4-yl-glycyl-dl-alanyl-dl-norvalyl-dl-asparagine). The cyclic peptide of the A. hamulosa honey was cyclo[Aad-RGD-d-F] (cyclo[Aad-Arg-Gly-Asp-d-Phe]). The Ziziphus honey was characterized by the presence of either Almiramide B or Auristatin-6-AQ. A. tortilis, A. hamulosa, and Ziziphus honeys are characterized by the presence of short and cyclic peptides which may contribute to their medicinal values.

A novel FeMoO4/g-C3N4-2D/2D Z-scheme heterojunction photocatalyst was prepared via wet chemical method. The observed structural morphology of FeMoO4/g-C3N4 reveals the 2D-iron molybdate (FeMoO4) nanoplates compiled with the 2D-graphitic carbon nitride (g-C3N4) nanosheets like structure. The photocatalytic activity of the g-C3N4, FeMoO4, and FeMoO4/g-C3N4 composites were studied via the degradation of Rhodamine B (RhB) as targeted textile dye under visible light irradiation (VLI). The optimal FeMoO4/g-C3N4 (1:3 ratio of g-C3N4 and FeMoO4) composite show an enhanced degradation performance with rate constant value of 0.02226 min-1 and good stability even after three cycles. Thus, the h+ and O2•－are the key radicals in the degradation of RhB under VLI. It is proposed that the FeMoO4/g-C3N4 Z-scheme heterojunction effectively enhances the transfer and separation ability of e-/h + pairs, by the way increasing the photocatalytic efficiency towards the RhB degradation. Thus, the newly constructed Z-scheme FeMoO4/g-C3N4 heterojunction photocatalyst is a promising material for the remediation of wastewater relevant to elimination of toxic effect in marine environment.

Here, for the first time, neodymium was incorporated into the three-dimensional mesoporous siliceous material; TUD-1. In order to understand the chemical and morphological structure of the prepared material, several characterization techniques were performed. The characterization results showed the formation of highly distributed isolated Nd3+ ions incorporated in the silica matrix in tetrahedrally coordinated structure, moreover no aggregation of separate phase(s) was/were observed. The prepared material was investigated as an adsorbent for methyl green (MG) dye in aqueous solution as a model cationic dye. The results showed higher adsorption capacity for Nd-TUD-1 by almost 24 times higher than the neat parent TUD-1 material and more than 100 times higher than bulky Nd2O3 under neutral pH. The adsorption results were fitted perfectly with pseudo-second-order model. Moreover, the adsorption isotherms were perfectly fitted with Freundlich isotherm model which indicated the formation of a multilayer of the dye molecules onto the Nd-TUD-1 surface as a physisorption with endothermic nature.

The structural and phase analysis of Li@ZnO nanostructures (NSs) were tested by X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM exhibits the mixture of nanoflakes and nanoparticles at 1 wt% Li, and spherical shaped nanoparticles at 7 wt%, respectively. TEM images show the nanoflakes with thickness (12–37 nm) and diameter of nanoparticles (38–63 nm) at 1 wt%, and size of nanoparticles with 34–84 nm at 7 wt%, respectively. Raman spectra exhibit the two major modes at 107 and 446 cm−1 were credited to longitudinal phonon modes. The optical bandgaps of 3.277–3.289 eV were evaluated from the optical spectra on basis of Kubelka–Munk function F(R) using Tauc’s relation. Red shift in absorption coefficient with wavelength indicates the optical bandgap decreased with increasing Li contents above 3 wt%. The photocatalytic activity of pristine and Li@ZnO NSs were investigated in the photodegradation of organic dye methylene green (MG) solution under UV irradiation. The photocatalytic study showed significant activity improvement in the Li-doped ZnO. The sample with 7 wt% Li-doped ZnO exhibited 6.1 times higher activity compared to neat ZnO sample.

This research, for the first time, reports the design and development of a heterogeneous nano-catalyst based on sodium ions (Na+) incorporation in Technical University of Delft (TUD-1) mesoporous silica for Knoevenagel condensation reaction. Facile one-step fabrication of Na-TUD-1 nano-catalysts (varying Si/Na ratio as 100–5) was demonstrated using the sol–gel route. The catalytic performance of Na-TUD-1 was evaluated as a base heterogeneous catalyst in Knoevenagel condensation reaction, which took place under conventional and microwave irradiations conditions using ethanol as a solvent. Na-TUD-1 exhibited superior catalytic activity in comparison to available homogeneous base catalysts such as sodium ethoxide. The Na-TUD-1 nano-catalyst demonstrated identical performance till the fourth run along with high stability and negligible leaching of Na. Moreover, the use of microwave heating reduced the reaction time from 240 to 20 min only with a TOF of 0.58 min−1. Such excellent performance of Na-TUD-1 heterogeneous nano-catalysts will certainly increase its industrial acceptability to achieve affordable and efficient waste-effluent treatments.

Nanoscale materials are of a foremost desirability in functionalized materials research in almost all areas of science. Nanoscale materials with good biocompatibility and chemical stability possess biomedical usages which comprises drug carrier, cell/DNA parting, wastewater cleaning etc. Hence, magnesium-doped ZnO (Mg@ZnO) nanoparticles (NPs) were prepared by combustion route. Crystallization of Mg@ZnO NPs was investigated using X-ray diffraction and transmission electron microscopy. The particle sizes were in the range of 50–130 nm and 17.5–52.5 nm for x = 1 wt% and 4 wt% in MgxZn1-xO samples, respectively. The Zn2+ substitution by Mg2+ in ZnO increased oxygen vacancies and reduced free electrons concentration. The concentrations of dopant dependent optical band gaps were calculated using diffuse reflectance and found in the range of 3.258–3.278 eV. Antibacterial study of Mg@ZnO NPs was conducted against the Gram- + ve and Gram – ve bacteria and results revealed enrichment in antibacterial activity of Mg@ZnO NPs against all types of bacteria. In vivo test revealed that all Mg@ZnO NPs have no cytotoxic effects on liver and kidneys. Furthermore, photocatalytic activity was performed towards hazardous methylene green dye degradation under UV light irradiation. The presence of Mg in ZnO lattice remarkably improved its photocatalytic performance and the photocatalytic activity of Mg@ZnO ranged from 1.8 to 5.4 times higher than the activity of neat ZnO under the same reaction conditions. Facile synthesis of Mg@ZnO NPs was achieved successfully through flash combustion process and the prepared NPs were exploited for optical, biological and environmental applications. Enhancement of antibacterial, cytotoxicity and photocatalysis activity was observed in ZnO with Mg content doping. The outcomes present the Mg@ZnO NPs as an efficient material for opto-bio-environmental applications.

Here, five different samples of neodymium (Nd) incorporated 3D-mesoporous siliceous materials were fabricated using a single-step hydrothermal technique. Typically, all samples were subjected to several qualitative elemental and quantitative analyses such as X-ray diffraction, N2 -adsorption/desorption, scanning electron microscopy, energy dispersive X-ray, mapping, high resolution transmission electron microscopy, diffuse reflectance ultraviolet-visible, and Raman spectroscopy. The characterization results showed that at small loading of Nd (i.e. Si/Nd < 20), only isolated centres of trivalent neodymium ions were tetrahedrally coordinated in the TUD-1 matrix. However, with increasing neodymium loading, additional nanoparticles of neodymium oxide with size 10-20 nm were embedded into silica host pores. Detailed photoluminescence (PL) analysis of all samples was carried out by recording the emission profiles at two diverse excitation wavelengths, 333 and 343 nm, to understand the effect of the Nd3+ environment on the PL emission spectra with special attention to the area between 400 and 600 nm. Most importantly, different peaks of the emission spectrum of each sample exhibited a distinct shape based on the Nd3+ environment. This performance was superior evidence that PL can be applied as a simple and efficient characterization tool to understand the nature of Nd3+ ion linkage with a silica matrix.

The facile synthesis of pristine and Terbium@Zinc oxide (Tb@ZnO) samples was produced by fast combustion route. The roughly spherical shaped morphology of Tb@ZnO was investigated by field emission scanning electron microscopy (FESEM) with agglomerated images of small size of particles. The dimension of particle shrinkages with increased the doping contents of Tb into ZnO lattice. The optical band gap of Tb@ZnO sample varies with the concentration of Tb and found to be decreased as 3.276, 3.267, 3.261 and 3.260 eV on increasing concentration of Tb from 1 to 5 wt%. The non-polar phonon mode with E2 symmetry was observed at 99 and 437 cm−1 while polar mode with A1 and E1 symmetry was reported at 330 and 580 cm−1, respectively, for pristine and Tb@ZnO samples. The photocatalytic activity of Tb@ZnO NPs has been investigated by the decolorization of methylene green (MG) dye under black light irradiation (367 nm). A remarkable photocatalytic performance of Tb@ZnO was noticed compared to the pure one and the highest percentage of activity was obtained for 1.0 wt% Tb@ZnO. Current outputs proposed the use of synthesized Tb@ZnO NPs in optoelectronic and photocatalyst applications.

Modernization and industrialization has undoubtedly revolutionized the food and agro-industrial sector leading to the drastic increase in their productivity and marketing thereby accelerating the amount of agro-industrial food waste generated. In the past few decades the potential of these agro-industrial food waste to serve as bio refineries for the extraction of commercially viable products like organic acids, biochemical and biofuels was largely discussed and explored over the conventional method of disposing in landfills. The sustainable development of such strategies largely depends on understanding the techno economic challenges and planning for future strategies to overcome these hurdles. This review work presents a comprehensive outlook on the complex nature of agro-industrial food waste and pretreatment methods for their valorization into commercially viable products along with the challenges in the commercialization of food waste bio refineries that need critical attention to popularize the concept of circular bio economy.

Here, for the first time, europium was incorporated into the open-structure three-dimensional mesoporous siliceous material. Samples with different loadings of europium were synthesized through one-step hydrothermal treatment based on sol-gel technique. The prepared samples were characterized by different characterization techniques and the results showed the formation of isolated trivalent europium ions in silica matric at low loading samples. However, at high loading samples, nanoparticles of europium III oxide, with an average size of 5–10 nm size, were detected inside the pores of mesoporous silica matrix. The photoluminescence property of the prepared samples was investigated at two different excitation wavelengths of 393 nm and 466 nm. The maximum photoluminescence emission intensity peaks was observed at approximately 614 nm at the two-excitation wavelength. The intensity of emission peak for the 614 nm was also found to be enhanced with increasing the loading of europium ions, this signify that europium acts as a good luminescent activator for red phosphor.

This report, for the first time, demonstrated the low-temperature oxidation of carbon monoxide (CO) using nano-catalysts consisting of noble metal nanoparticles incorporated in TUD-1 mesoporous silica nano-structures synthesized via a one-pot surfactant-free sol&ndash, gel synthesis methodology. Herein, we investigated a nano-catalyst, represented as M-TUD-1 (M = Rh, Pd, Pt and Au), which was prepared using a constant Si/M ratio of 100. The outcome of the analytical studies confirmed the formation of a nano-catalyst ranging from 5 to 10 nm wherein noble metal nanoparticles were distributed uniformly onto the mesopores of TUD-1. The catalytic performance of M-TUD-1 catalysts was examined in the environmentally impacted CO oxidation reaction to CO2. The catalytic performance of Au-TUD-1 benchmarked other M-TUD-1 catalysts and a total conversion of CO was obtained at 303 K. The activity of the other nano-catalysts was obtained as Pt-TUD-1 &gt, Pd-TUD-1 &gt, Rh-TUD-1, with a total CO conversion at temperatures of 308, 328 and 348 K, respectively. The Au-TUD-1 exhibited a high stability and reusability as indicated by the observed high activity after ten continuous runs without any treatment. The outcomes of this research suggested that M-TUD-1 are promising nano-catalysts for the removal of the toxic CO gas and can also potentially be useful to protect the environment where a long-life time, cost-effectiveness and industrial scaling-up are the key approaches.

In the current study, for first time trivalent lanthanum (La) ions was incorporated with different loading into the 3D-sponge-like structured of TUD-1 mesoporous material. All fabricated materials were synthesized via applied one-pot sol-gel hydrothermal method. Different physical and chemical characterization techniques such as ICP, XRD, SEM, EDX, mapping, N2-sorption, DR-UV-Vis, HR-TEM, Raman and XPS were applied to characterize the synthetized materials. The prepared materials confirmed the formation of isolated active sites at low loading of lanthanum La+3 ions into TUD-1 silica matrix. On the another side, the nanoparticles of La2O3 with average size 10–50 nm of oxide crystals were found into the pores of TUD-1 at high loading of Lanthanum. The photoluminescence (PL) property of the synthetized samples were investigated under different excitation wavelengths ranged from UV to visible illumination. La-TUD-1 showed exhibited high emission PL spectra under the illumination of 346 nm, 380 nm, 470 nm, and 580 nm wavelength. The obtained PL emission bands are related to blue and green emission and hence can be employed as promised blue-green LEDs and biological labeling in different future application.

A direct and simple one-step procedure was applied to prepare gold (Au) nanoparticles (NPs) embedded in graphitic carbon nitride (g-C3N4) sheets. Four samples with different Au contents (from 0.5% to 5% wt) were prepared via thermal polymerization of melamine at 550 °C in the presence of commercial Au NPs after careful mixing using a ball mill. The prepared samples were characterized by XRD, DR-UV-Vis, Raman spectroscopy, XPS, SEM and HR-TEM. Characterization data confirmed the presence of zero-valent gold nanoparticles (Au0 NPs) on the g-C3N4 lattice without any chemical changes after the synthesis. The lattice constraints were found to vary with varying Au content; however, they were very close to those of the pure g-C3N4 sample. Moreover, as the Au content increased, the band gap calculation showed no significant shift, and the band gap did not change. The photocatalytic activity of the prepared samples was investigated in the decolourization reaction of Arsenazo III dye (ArIII) dye aqueous solution under visible light illumination (420

A facile process has been employed to prepare the high quality ZnO nanostructures with different contents of Iron (Fe) doping. X-ray diffraction analysis confirms the synthesis of monophasic ZnO at all Fe contents and rules out the formation of secondary phase. The Scherrer formula was used to determine the particle size and noticed to be reduced from 23 nm to 9 nm when Fe doping increased from 0 to 7.5 wt%. Scanning electron microscopy study shows that the particle are of spherical shape and the size is reducing with Fe content. EDX/SEM elemental-mapping analysis confirm the synthesis of Fe doped ZnO, with homogeneous Fe distribution. A systematic reduction of energy gap was noticed from 3.287 to 3.212 eV. The photocatalytic activity of ZnO was systematically enhanced with Fe content and highest was noticed for 7.5 wt% Fe@ZnO SNPs and also degradation mechanism has been discussed.

In the current study, four new catalysts were synthetized by using TUD-1 mesoporous material as a support for bi-metallic Noble metals nanoparticles. M-Au-TUD-1 (M = Rh, Pd, Pt, and Ag) were prepared with a total metals loading of 2 wt% by applying the ratio of 1Au:1M. Several physical and chemical characterizations were performed to understand the structure of the prepared catalysts. The characterization results showed the formation of bi-metallic alloys between Au and Pd, Rh or Ag, while the formation of alloy between Au and Pt was not confirmed under the applied synthesis conditions. The formed bi-metallic alloy nanoparticles were found to be highly distributed through the mesoporous silica and the average size of the formed nanoparticles was 15–30 nm. The prepared samples were investigated to catalyze the environmentally impacted reaction of carbon monooxide (CO) oxidation to carbon dioxide (CO2). The catalytic efficiency of Ag–Au catalyst was higher than the other investigated catalysts, 100% of CO gas was converted over Ag–Au catalyst at 25 °C. Moreover, Pt–Au and Pd–Au catalysts exhibited similar activity to bare Au nanoparticles. Moreover, the stability of the four investigated catalysts was investigated by using the same catalytic sample in ten consecutive reactions without treatment, Rh–Au-TUD-1 and Pt–Au-TUD-1 exhibited the highest stability, while, Ag–Au showed partial deactivation due to the oxidation of Ag to Ag2O.

In current work, silver sulfide nanoparticles (Ag2S NPs) were prepared in presence of 0.0, 0.1, 0.25.0.5 and 1.0 g of sodium dodecyl sulfate surfactant (named as S1, S2, S3, S4 and S5) though a microwave assisted route within 10 min of irradiation at 700 W power. XRD established decent crystalline nature of the prepared Ag2S NPs of crystallite size in range from 44 to 49 nm. Scanning electron microscopy showed that the synthesized particles have three-dimensional irregular shape, very close to fused-spheres or worm-like structure. More importantly; the size of the particles is decreased with the amount of the applied SDS surfactant. Kubelka-Munk relation was used to evaluate energy gap and noticed ~1.014 for S1, 1.017 eV for S2, 1.021 eV for S3, 1.023 eV for S4, and 1.026 eV for S5 samples, i.e. the energy gap is slightly increase with the amount of the applied SDS surfactant. The estimated refractive index values are noted in 1.51–2.2 range. Dielectric constant (e1), loss tangent (tanδ) and dielectric loss (e2) were calculated and shows high values of e1 and low values of tanδ. The photocatalytic performance was examined in methyl green dye photocatalytic decolourization under illumination of UV/visible light. Ag2S samples exhibited excellent photocatalytic behavior, hence can be used in water treatment applications.

The different concentrations of 0.0, 1.0, 2.5 and 5.0 wt% Cu-doped ZnO (Cu@ZnO) nanoparticles (NPs) have been synthesized for opto-photocatalytic applications by a facile and cost-effective route. The formation and structural analyses of Cu@ZnO NPs was recognized by X-ray diffraction (XRD), Fourier transform (FT)-Raman and Transmission electron microscopy (TEM). The average crystallite size of 28.9, 27.4 and 26.4 nm was calculated for (101) intense peak and found to be decreased with increasing the contents of Cu. The residual microstrain values are noted ~3.84 × 10−3, 4.03 × 10−3 and 4.19 × 10−3. The particle size of 170, 109, 127 and 175 nm is obtained for undoped and Cu doped ZnO NPs from FESEM. The optical band gap of Cu@ ZnO NPs were estimated through Kubelka-Munk theory and noted ~3.225, 3.150, 3.100 and 2.995 eV for 0.0, 1.0, 2.5 and 5.0 wt% Cu@ZnO NPs; this shows decreases with increasing the Cu contests in ZnO lattice. Photoluminescence (PL) spectra of Cu@ZnO NPs shows near band edge emission at 407–411 nm with emission band 565-572 nm correspond to intrinsic defects in ZnO lattice. The photocatalytic performance of Cu@ZnO NPs was assessed through decolourizing of methyl green beneath the visible light illumination (λ = 425–460 nm). Photocatalytic action of Cu@ZnO samples was 3.5 times greater to neat ZnO. Photocatalytic properties of Cu@ZnO NPs can be used for water purification in environmental applications.

The successful one pot flash combustion synthesis of ZnO nanoparticles (NPs) with a diverse LA (La@ZnO) content was achieved simply and economically. X-ray diffraction confirms the synthesis of ZnO with a hexagonal crystal system. The vibrational bands are positioned at 100, 332, 380, 438 and 583 cm−1 for pure and La@ZnO NPs. FESEM images exhibit roughly spherical and oval morphologies of pure ZnO with particles size 120 nm and La@ZnO NPs with particle sizes in the 46–74 nm range. The particle size of a La doped ZnO sample increases with increase in concentration from 1.0 % to 7.5 wt.% of La. The evaluated energy gap of La doped ZnO NPs decreased from 3.220 to 3.210 eV as the concentration of La varied from 1.0–7.5 wt.% as estimated by Kubelka–Munk theory. The photocatalytic analysis of the as-synthesized ZnO nanoparticles is maximized at La (1.0 wt.%) and the mechanism of photocatalytic decolourization reaction is discussed. The results suggest that the La-doped ZnO nanoparticles can be used in optoelectronic and photocatalytic applications.

Zinc oxide is well-known material and used in several applications. We have synthesized the good quality ZnO nanoparticles with different concentrations of Strontium (Sr) doping for photocatalytic applications. The elemental composition and homogeneous distribution of Sr doping in ZnO was investigated through EDX/SEM mapping. The morphology of synthesize products was studied through FE-SEM and grain size was estimated. X-ray diffraction (XRD) and FT-Raman spectroscopy analyses approves the single phase and purity of synthesized Sr:ZnO NPs as no additional peak in XRD and Raman was seen. The size of crystallites was estimated using Scherrer equation and noticed to be reduced from 24 to 16 nm with rising the Sr concentration. The energy gap was estimated using Kubelka-Munk function and noticed in range from 3.25–3.27 eV with Sr concentration. The photoluminescence spectra were recorded for all Sr:ZnO NPs at λexc =350 nm. The photocatalytic activity of Sr:ZnO NPs samples was investigation by decolourization of methylene blue (MB) dye under irradiation of black-light in an aqueous solution at ambient conditions. A remarkable improvement in photocatalytic activity was obtained for the entire prepared Sr:ZnO samples compared to that of neat ZnO. Such improvement in photocatalytic activity can be attributed to the effective photogenerated charges separating, in addition to the good adsorption of MB dye molecules over Sr:ZnO NPs surface.

In the current article, two different functionalities were employed to enhance the photocatalytic performance of the two famous semiconductors; ZnO and TiO2, under UV light illumination. Eu3+ incorporated TUD-1 mesoporous material (Si/Eu ratio of 10) was wet deposited with ZnO and TiO2 with a mass ratio of 1 Eu-TUD-1: 1 ZnO or TiO2. The prepared composites were characterized by means of XRD, DR UV-Vis, Raman spectroscopy, SEM, EDX and HR-TEM. Characterization data confirmed the presence of Eu2O3 nanoparticles embedded in amorphous silica matrix that support the nanoparticles of commercial ZnO or TiO2. The photocatalytic performance of the prepared materials was examined in the decolourization reaction of methyl green (MG) dye under black light illumination with a wavelength centered at 367 nm and at ambient temperature. The activity of the prepared materials was almost 3.4-3.6 times higher than neat ZnO or TiO2 and almost 1.2-1.3 times higher than same composites without silica, under the same condition. The prepared composites were recycled successfully for four consecutive reaction without significant loss in the case of Eu-TUD-1/TiO2 composite and 18-20% of loss activity in the case of Eu-TUD-1/ZnO composite. Hence, the results suggest the application of prepared material as photocatalyst under UV illumination with strong adsorption affinity.