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In this work, the crystalline carbon nitride photocatalysts were synthesized by an ionothermal technique with varied synthesis temperature of 500, 550, and 600 °C, and synthesis time of 2, 4, and 6 h. Fourier transform infrared spectra showed the successful formation of the prepared carbon nitrides from their characteristic vibration peaks. X-ray diffraction patterns suggested that the same phase of poly(triazine imide) and heptazine could be observed, but with different crystallinity. The optical properties showed that different temperatures and synthesis time resulted in the different band gap energy (2.72–3.02 eV) as well as the specific surface area (24–73 m2 g–1). The transmission electron microscopy image revealed that the crystalline carbon nitride has a near-hexagonal prismatic crystallite size of about 50 nm. Analysis by high-performance liquid chromatography showed that the best photocatalytic activity for phenol degradation under solar light simulator was obtained on the crystalline carbon nitride prepared at the 550 °C for 4 h, which would be due to the high crystallinity, suitable low band gap energy (2.82 eV), and large specific surface area (73 m2 g–1). Controlling both the temperature and synthesis time is shown to be important to obtain the best physicochemical properties leading to high activity.

One green approach to degrade organic pollutants, such as phenol, is through the photocatalytic reaction. Despite having large band gap energy, which is enough for phenol degradation, zinc oxide (ZnO) has low photocatalytic efficiency. In this study, ZnO was modified by lanthanum (La) species, and the improved photocatalytic activity was confirmed for degradation of phenol under visible and ultraviolet (UV) light irradiation. The ZnO and its modified photocatalysts were prepared by the hydrothermal method in the absence and presence of La species (0.01‒2 wt%). X-ray diffraction (XRD) patterns showed that the addition of La did not disturb the structure of ZnO, but slightly decreased the crystallite size. While the La addition up to 1 wt% did not affect the optical properties of the ZnO, the addition of 2 wt% La slightly red-shifted the absorption band edge of the ZnO. The Fourier-transform infrared (FT-IR) spectra showed La oxide formation observed at 515-540 cm-1 after 2 wt% La addition. Fluorescence emission spectra revealed that synthesized ZnO has oxygen vacancies at 558 nm, and the presence of 1 wt% La did not significantly affect the emission intensity. The photocatalytic activity of ZnO was influenced by the La addition, where the best performance was obtained on the ZnO with 1 wt% La. This study demonstrated that the optimum amount of La species could increase the performance of the ZnO.

N’-(5-nitro-2-oxoindolin-3-ylidene) thiophene-2-carbohydrazide (NH) was successfully synthesized as a ligand, then grafted onto the surface of mesoporous silica SBA-15via an aminopropyl bridge. The successful grafting of ligand NH onto the hybrid nanomaterial (SBA-15/APTES-NH) was confirmed by infrared spectroscopy. On excitation at 276 and 370 nm, the ligand NH and the hybrid nanomaterial SBA-15/APTES-NH showed a strong and narrow emission peak centered at 533 nm. By dispersing SBA-15/APTES-NH in an aqueous solution containing metal ions, the resulting solid materials showed a higher binding of NH sensing site to Fe3+ ions as compared to the others with a quench of the emission intensity up to 84%. This result showed that the hybrid nanomaterial is a potential chemosensor that requires development for the detection of metal ions.

Mesoporous carbon nitride (MCN) having larger specific surface area and more defects exhibited higher photocatalytic activity than the bulk one for degradation of aromatic organic pollutants under visible light. The different substituent groups resulted in the different degradation percentages. It was suggested that benzene derivatives with high structure stability or containing electron-withdrawing group (EWG) led to the deactivation of the aromatic ring. Although benzene ring reactivity was accelerated by the presence of electron-donating group (EDG), it was also affected by other factors such as the easiness to be adsorbed onto the photocatalyst and formation of no stable intermediates.

Chemosensors with ultrasensing capabilities for detection of metal ions have received particular attention when using luminescent organic compounds. Even though hundreds of chemosensor agents have been reported for Fe3+ ion sensing, the designs of those molecules have been complicated and time consuming, in addition to having limited application for aquatic samples due to their poor hydrophilicity. Here, we synthesized a novel azo-imine derivative (L2) that showed ultrasensitive and selective sensing for Fe3+ ions. L2 exhibited ultraselective detection of Fe3+ ions with a turn-off of its emission intensity at 341 nm in H2 O:MeOH (4:1 v/v) aqueous medium. This quenching phenomenon was in good agreement with its colour change from orange-yellowish to colourless. Its capability was shown due to its very low limit of detection and limit of quantification values of 0.31 and 1.04 μM, respectively. The interference study showed that L2 is ultraselective for the detection of Fe3+ ions without a significant reduction in its sensing capability even in competitive metal mixtures. Furthermore, direct Fe3+ quantification of tap and drinking water showed that L2 gave good recovery percentages. These findings demonstrated that the Schiff's base with an azo fluorophore derivative is a potential chemosensor agent for Fe3+ ions sensing applications in aqueous media.

In this work, we reported the synthesis of green-emissive composite materials of zinc oxide (ZnO) and isolated betacyanin pigment from red dragon fruit (RDF) extract utilizing organic linkers, i.e. (3-chloropropyl)trimethoxysilane (CPTMS) and (3-aminopropyl)trimethoxysilane (APTMS). Betacyanin was extracted using a maceration technique, while CPTMS-ZnO and APTMS-ZnO were prepared by mixing ZnO and the respective organic linker in ethanol. The obtained ZnO/CPTMS and APTMS-ZnO composites were separately added into the RDF extract, followed by stirring at room temperature for 24 h. As high as 80 and 90% of betacyanin was successfully impregnated onto CPTMS-ZnO and APTMS-ZnO, respectively. A comparison study was made by preparing RDF-CPTMS and RDF-APTMS first and then introducing them onto ZnO. In this case, as high as 81 and 100% of betacyanin in RDF-CPTMS and RDF-APTMS, respectively, were impregnated onto ZnO. These results revealed that APTMS was a better organic linker than CPTMS and the order of the steps to introduce APTMS was important. The presence of betacyanin on the composite materials was confirmed by FTIR and fluorescence spectroscopy. All the composite materials had an excitation signal at 426–428 nm and emission signals at 459 and 517–518 nm, demonstrating their promising application as green-emissive materials.

Zinc oxide (ZnO) is one of the semiconductor photocatalysts having large band gap energy, which is usually enough for the degradation of organic pollutant such as phenol. However, large band gap energy also means that ZnO is mostly active under UV light only. In this study, ZnO was sensitized using a methyl red dye and the improved photocatalytic activity was confirmed for degradation of phenol under visible light irradiation. The ZnO was first prepared by a hydrothermal method, then was sensitized with methyl red (MR) dye through an impregnation method with various contents of MR (1-3 wt%). Fourier transform infrared spectra indicated a change in methyl red structure after impregnation on ZnO due to the basicity of ZnO. While the MR addition did not affect the band gap energy of ZnO, it improved the optical properties of ZnO in the visible light region. Fluorescence spectra revealed that the addition of 1 and 2 wt% MR slightly red-shifted the excitation maxima of ZnO, while 3 wt% addition resulted in a blue-shift. Furthermore, it was shown that ZnO has an oxygen vacancy with emission at 558 nm and the presence of methyl red quenched the emission intensity. The photocatalytic activity of ZnO increased after dye sensitizing, where the best performance was obtained on the ZnO with 2 wt% of MR addition. The better photocatalytic activity of ZnO after dye sensitization could be proposed due to the additional electron transfer from MR to ZnO generated under visible light irradiation.

Development of visible-light-active photocatalyst is an important approach to utilize solar energy in the future. The attempts to improve the crystallinity of photocatalyst have been the focus of the research. Recently, the use of potassium chloride-lithium chloride (KCl-LiCl) salt melt has been reported to increase the crystallinity of carbon nitride. In this work, precursor and salt melt amounts were varied to study the properties and the photocatalytic activity of the crystalline carbon nitride for phenol degradation. When the precursor amount was too low (1 g), no product was obtained due to the decomposition of precursor. When it was too high (4 g), the product showed the characters of amorphous CN. Optical properties also showed that when the precursor amount was 3–4 g, the incomplete condensation process occurred and defects were formed due to the excessive washing. The specific surface area also decreased with the increase of the precursor amount from 2 to 4. When the amount of salt melt was too low (2.5 g), the crystalline CN could not be obtained. However, when the amount of salt melt was increased to 7.5 g, impurities could not be avoided. Longer time and multiple washing processes were required in order to remove the impurities, which certainly affected the crystallinity. Photocatalytic activity test showed that the high activity was obtained on the sample prepared using the optimum amount of precursor (2 g) and salt melt (5 g), which would be due to the high crystallinity and large specific surface area.

Nitrite ion (NO 2 - ) is a toxic inorganic contaminant, which is widely used in industry and agriculture as a food preservative and a fertilizing agent. One of the methods to reduce the toxicity of the NO 2 - is by oxidizing it into less hazardous compounds, such as nitrate ion (NO 3 - ). In this study, we demonstrated that a simple and green photocatalytic process can be employed to oxidize the NO 2 - to NO 3 - over a metal free-carbon nitride photocatalyst under ultraviolet (UV) light irradiation. The carbon nitride was synthesized via pyrolysis of urea precursor by a thermal polymerization process at 823 K for 4 hours. The prepared carbon nitride was then characterized by using X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), diffuse reflectance UV-visible (DR UV-vis), fluorescence, and Fourier transform infrared (FTIR) spectrophotometers, as well as nitrogen adsorption-desorption isotherm analyzer. All the characterization results supported the successful synthesis of the carbon nitride. The carbon nitride was then used as the photocatalyst for oxidation of NO 2 - to NO 3 - under UV light irradiation for 3 h. The decrease of the NO 2 - and the formation of the NO 3 - were analyzed by using a high performance liquid chromatography (HPLC) equipped with Hypersil Gold TM PFP column. The mobile phase used was a mixture of methanol (MeOH) and water (H 2 O) with the ratio of MeOH:H 2 O was 30:70. The addition of orthophosphoric acid was required to set the pH at 2.5. The flow rate was fixed at 0.8 ml min -1 and the monitored wavelength was 220 nm. It was revealed that carbon nitride could oxidize NO 2 - to NO 3 - with a moderate conversion of 15%. Fluorescence quenching showed that there were good interactions between the emission sites of carbon nitride and the NO 2 - molecules. The good interactions would be one driving force for the carbon nitride to act as a good photocatalyst to oxidize the NO 2 - to NO 3 - . The oxidation pathway by the photogenerated species was also proposed.

Column gravity chromatography suffered from several drawbacks such as time-consuming and need a large amount of eluents. Herein we reported an efficient technique for effective separation of amphiphilic trinuclear gold(I) pyrazolate complex ([Au 3 Pz 3 ] C10TEG ) with high polarity based on size-exclusion principle of chromatographic technique. Based on the size-exclusion limit, [Au 3 Pz 3 ] C10TEG having a larger size with molecular weight of 4011.39 Da (4030.40 Da when added Na + ) was successfully eluted and collected firstly from its impurities after being recycled for 2 times. In the chromatogram for first cycle, an intense peak upon excitation at 220 nm for [Au 3 Pz 3 ] C10TEG was observed at retention time of 58 mins, while small peaks due to the presence of impurities was observed in the range between 73 to 85 mins. In the second cycle, the impurities were flushed away before [Au 3 Pz 3 ] C10TEG was successfully collected at retention time of 170 mins in the third cycle. The columns were a set of polystyrene/divinylbenzene (PS/DVB) JAIGEL-1H and -2.5H connected in series having exclusion limit of 1 X 10 3 and 2 X 10 4 in which chloroform was used as the eluent at flow rate of 3.5 mL min -1 . As a result, the visual appearance of dark-yellowish [Au 3 Pz 3 ] C10TEG was successfully purified to give pale-yellowish product. Moreover, differential scanning calorimetry thermogram showed that extra shoulder from impurities at 6.13 °C in the first endothermic peak of [Au 3 Pz 3 ] C10TEG at 0.76 °C was completely removed. Hence, it can be concluded that size-exclusion chromatography can be used as an effective purification method with much more convenience and small consumption of solvents.

Special attention has been given to red dragon fruit (Hylocereus polyrhizus) because of its unique natural compounds exhibiting wide biological activities. However, the potential use of the red dragon fruit peel has been less addressed. In the present work, simple extraction of red dragon fruit peel was carried out to study the fluorescence properties of the corresponding extracts in various solvents. The red dragon fruit peel was first separated, dried, and macerated for 24 hours using distilled water, ethanol, and acetone, separately. The results demonstrated that the peel extracts exhibited different photoluminescence properties depending on the solvent type. It was revealed that the ethanolic extract gave the highest fluorescence intensity among the other extracts. The ethanolic extract showed two excitation peaks at 290 and 359 nm, yielding different emission properties. Excitation at 290 nm gave one emission peak at 339 nm, while the excitation at 359 nm gave an emission peak at 436 nm. Such strong photoluminescence properties observed in the wide range of UV and visible regions demonstrated the potential use of the red dragon fruit peel as a photonic material. Spectroscopy study also proposed that the ethanolic extract would have polyphenol and chlorogenic acid as the main compounds.

2,4-dichlorophenoxyacetic acid (2,4-D) has been recognized as a possibly carcinogenic compound to human, therefore, 2,4-D should be treated before it is discharged to the environment. Photocatalytic degradation of 2,4-D has been proposed as one of the best methods that offer environmentally safe process. In the present research, titanium dioxide (TiO2) was modified with cobalt oxide (CoO) and tested for photocatalytic degradation of 2,4-D under UV light irradiation. Different amounts of CoO (0.1, 0.5, 1 and 5 mol%) were added onto TiO2 by an impregnation method. The photocatalytic reaction was monitored and analyzed by measurement of 2,4-D absorbance using UV spectrophotometer. After 1 h photocatalytic reaction, it was confirmed that the sample with low loading of 0.1 mol% gave the highest photocatalytic activity among the bare and modified TiO2 photocatalysts. The photocatalytic activity was decreased with the increase of CoO loading, suggesting that the optimum amount of CoO was an important factor to improve the performance of TiO2. Based on fluorescence spectroscopy, such addition of CoO resulted in the reduced emission intensity, which showed the successful decrease in the electron-hole recombination.

A series of composites containing reduced graphene oxide and zinc oxide (rGO-ZnO) with optimum GO loading amount of 3 wt% was successfully synthesized through an in-situ photocatalytic reduction of graphene oxide (GO) over ZnO photocatalyst under UV light irradiation. Different light intensities and exposure times were confirmed to affect the properties and photocatalytic performance of the rGO-ZnO for photocatalytic degradation of phenol as an organic pollutant model. The best photocatalyst was obtained under UV light intensity of 0.4 mW cm−2 for 24 h exposure and it gave around three times higher photocatalytic performance than that of the bare ZnO. Compensating for the long exposure time, such low light intensity was crucial to generate rGO with low amount of defects. The low amount of defects resulted in low electron-hole recombination, low resistance of a charge transfer, and high electron-transfer rate constant, which in turn enhanced the photocatalytic performance. Reusability tests demonstrated the potential use of rGO-ZnO as a good photocatalyst for organic pollutant degradations.

Two series of Fe2O3/TiO2samples were prepared via impregnation and photodeposition methods. The effect of preparation method on the properties and performance of Fe2O3/TiO2for photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV light irradiation was examined. The Fe2O3/TiO2nanocomposites prepared by impregnation showed lower activity than the unmodified TiO2, mainly due to lower specific surface area caused by heat treatment. On the other hand, the Fe2O3/TiO2nanocomposites prepared by photodeposition showed higher photocatalytic activity than the unmodified TiO2. Three times higher photocatalytic activity was obtained on the best photocatalyst, Fe2O3(0.5)/TiO2. The improved activity of TiO2after photodeposition of Fe2O3was contributed to the formation of a heterojunction between the Fe2O3and TiO2nanoparticles that improved charge transfer and suppressed electron–hole recombination. A further investigation on the role of the active species on Fe2O3/TiO2confirmed that the crucial active species were both holes and superoxide radicals. The Fe2O3(0.5)/TiO2sample also showed good stability and reusability, suggesting its potential for water purification applications.

Nitrogen containing compounds such as nitrite ions (NO2 -) may cause contaminations to the environment, food and drinking water, and they have a negative effect on human health. In this study, a novel fluorescence sensor was developed by modification of polymeric carbon nitride (CN) with copper(II) acetylacetonate (Cu(acac)2). The polymeric CN was prepared by using urea as a precursor via thermal polymerization technique, while the Cu(acac)2 was introduced onto the polymeric CN via an impregnation method. The formation of polymeric CN can be confirmed from the Fourier transform infrared (FTIR) and the diffuse reflectance ultraviolet visible (DR UV-Vis) spectroscopies. The polymeric CN exhibited three excitation peaks at 277, 315, and 370 nm owing to the presence of CN, CO, and CN groups, respectively, while there was only one emission peak observed at 455 nm. The emission intensity was decreased with the increase of Cu(acac)2 loading, suggesting certain interactions between the polymeric CN and the added Cu(acac)2. The performances of the polymeric CN and Cu(acac)2/CN composites as fluorescence sensors were evaluated for (NO2 -) detection with concentration range of 0.5-4 μM. It was revealed that the CN sites in the polymeric CN were the most favored quenching sites for the (NO2 -). With the addition of Cu(acac)2 (0.1 mol%), the quenching rate for CN sites was enhanced two times higher than that of the polymeric CN. This study demonstrated that the composite is a promising fluorescence sensor for the detection of (NO2 -).

Series of lanthanum-modified TiO2 catalysts were prepared by a UV photodeposition method to exclude any heat treatments that may affect the properties and photocatalytic activity of TiO2. Results showed that the lanthanum modification did not significantly affect the properties of TiO2, but increased the formation of Ti3+. Under UV light irradiation, the activity for 2,4-D decomposition rose by a maximum factor of 5.5 when TiO2 was loaded with 5 mol% La; further increase of La deposition led to a decrease in photocatalytic activity. From the electrochemical impedance and photocurrent results, it was shown that the positive influence of La on TiO2 photocatalytic activity was caused by the increased charge separation in the TiO2 photocatalysts, owing to the additional formation of Ti3+ states. On the other hand, when tested with the colourless 2,4-D model pollutant under visible and solar simulator irradiation, the presence of lanthanum species did not improve the photocatalytic activity of TiO2 significantly. Hence, it was shown that lanthanum species only improved the UV photocatalytic activity of TiO2.

Crystallinity could have a decisive influence on photocatalytic performance. In this study, the synthesis of crystalline carbon nitride (CN) was studied via an ionic melt polycondensation of urea precursor in the presence of various salt melts, which were KCl-LiCl, KCl-NaCl, and KCl-ZnCl$_{2}$. While all the salt melts helped to improve the optical properties of the CN, only KCl-LiCl salt melt could form crystalline CN as evidenced by its X-ray diffraction pattern. Furthermore, the specific surface area of CN (72 m$^{2}$/g) was maintained when using KCl-LiCl (73 m$^{2}$/g), but it was decreased in the presence of KCl-NaCl (22 m$^{2}$/g) or KCl-ZnCl$_{2}$ (17 m$^{2}$/g). The CN prepared without the salt melt only showed 10% phenol degradation under the light of a solar simulator, while the use of KCl-LiCl significantly improved the activity to 24%. On the other hand, the CN prepared in the presence of KCl-NaCl and KCl-ZnCl$_{2}$ gave phenol degradation of 14% and 7%, respectively. This work demonstrated that the crystallinity, improved absorption in the visible light region, and maintained large specific surface area of the CN were crucial to achieve the high activity.

Dimers and trimers of a fluorenone-appended porphyrin were prepared via Lindsey optimized Sonogashira coupling reaction. The photophysical properties of the oligomers were investigated upon excitation of the fluorenone arms which act as donors. The emission profiles of the covalently linked porphyrins suggest that the diphenylacetylene bonds are vital for efficient intramolecular energy transfer between the porphyrin units. Additionally, higher fluorescence quantum yields were recorded for the oligomers than for the individual units.

Synthetic metalloporphyrins have long been recognized either as functional models or mimics of the cytochrome P-450 enzymes and they are versatile compounds with potential use in drug delivery, catalysis and electronics. In the present study, the metalloporphyrin, (meso-tetra-(p-sulfonatophenyl)-porphyrinato)copper, CuTSPP was synthesized in the reaction between free-base porphyrin, meso-tetra (p-sulfonatophenyl)porphyrin, H2TSPP and copper(II) acetate monohydrate. The materials were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible (UV-Vis) Spectroscopy, Proton Nuclear Magnetic Resonance (1H NMR) Spectroscopyand Mass Spectrometry (MS) analysis. The FTIR spectra of both free-base porphyrin and CuTSPP showed the appearance of three pronounced bands indicating the presence of the salt form (R-SO3Na) of the sulfonic acid group. Characterization of CuTSPP by UV-Vis spectroscopy confirmed that the insertion of copper into the free-base porphyrin was successful by the appearance of the Soret band and Q bands. The catalytic activity of CuTSPP was tested in the oxidation of 2,3,6-trimethylphenol (TMP) at 60 °C using hydrogen peroxide (H2O2) as oxidant. The reaction parameters including the reaction temperature and time have been optimized. The only product obtained by means of TMP oxidation with H2O2 using CuTSSP is 2,3,5-trimethylbenzoquinone (TMBQ), an important precursor for the industrial production of Vitamin E.

Here phosphorescent trinuclear copper (I) pyrazolate complexes ([Cu3Pz3]), synthesized from 3,5-dimethyl and 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligands for complexes [Cu3Pz3]1 and [Cu3Pz3]2, were successfully impregnated into TiO2 with concentration of 0.1 mol%. These luminescent photocatalyst composites ([Cu3Pz3]1or 2/TiO2) gave 60% and 49% of dichlorophenoxyacetic acid (2,4-D) degradation after 1 h for [Cu3Pz3]1/TiO2 and [Cu3Pz3]2/TiO2, while TiO2 only showed 48%. The higher activity observed on [Cu3Pz3]1/TiO2 than the TiO2 would come from the efficient reduction of electron-hole recombination, while less dispersion of complex [Cu3Pz3]2 with more rigid structure compared to complex [Cu3Pz3]1 gave similar activity of the [Cu3Pz3]2/TiO2 to the TiO2.

Porous montmorillonite (PMMT) was derived from natural montmorillonite (MMT) through functionalization using 3-aminopropyltrimethoxysilane (APTMS) and intercalation with cationic potato starch as the template. Phosphotungstic acid (HPW) supported on PMMT was synthesized by wet impregnation method. The resulting PMMT showed remarkable increase in surface area from the low value of 191 m2g‒1 for parent MMT to the high value of 930 m2g‒1 for PMMT. Acidity studies by pyridine adsorption followed by FTIR spectroscopy showed that both MMT and PMMT possessed strong Lewis acid sites. In contrast, the surface acidity of HPW incorporated into PMMT was shown to be significantly enhanced by forming mainly Brönsted acid sites. The catalytic activity of these materials was evaluated in the Friedel-Crafts acylation of anisole with propionic anhydride. The PMMT/30HPW catalyst which possesses the highest number of Brönsted acid sites showed excellent catalytic activity giving selectivity as high as 95% toward the main product, p-methoxypropiophenone.

2,4-Dichlorophenoxyacetic acid (2,4-D) is a common herbicide that has been used in control of broadleaf weeds, wheat, corn, pastureland, lawn, recreational lakes, turf; and roadsides. Due to it excessive usage, these herbicides that contained 2,4-D can cause contamination over agricultural land and water bodies. Photocatalytic removal environmental pollutants such as herbicides has been a topic of great interest over the years 1. One of the most widely used materials for photocatalytic degradation of environmental pollutants is TiO,. A number of strategies have been developed in order to improve the catalytic activity of TiO, photocatalyst. In particular, it has been shown that transition metal oxides, such as copper oxide, are potential to enhance the photocatalytic activity of TiOl". In the present work:, a simple impregnation method was used to modify the commercial P25 TiD, nanoparticles with the copper oxide. The prepared samples were characterized by XRD, reflectance UVvisible and fluorescence spectroscopies. It was observed that the incorporation of copper oxide did not significantly affect the crystal structure of TiD,. On the other hand, the presence of copper oxide was confirmed by reflectance UV-visible and fluorescence spectroscopies. Figure I shows the photocatalytic removal of 2,4-D on bare TiD, and modified TiO,nanoparticles. It can be clearly shown that after I hour reaction, the photocatalytic activity of TiD, increased from 48 to 54% with the increase of copper oxide loading up to 0.5 mol%. Unfortunately, the higher loading amount of copper oxide resulted in the lower photocatalytic activity. When the loading amount was 5 mol%, the activity decreased to 26%. This result clearly suggested that the small amount of copper oxide, which was 0.5 mol%, was the optimum amount in this study to give the highest activity for the copper oxide supported on TiD, series. The higher photocatalytic activity would be originated from the lower electron-hole recombination.

Phenol is a stable and hazardous compoundthat is commonly found as an industrial effluent 1. Phenol can be treated by photocatalysis using ZnO as a photocatalyst'' 3. Unfortunately, the use of zinc oxide (ZnO) in photocatalysis is limited due to the photocorrosion effect and poor response to the visible light", Various methods have been reported to improve the performance of ZnO,such as the use of carbon nitride (C3N4) to suppress the photocorrosion and improve the absorption in the visible light regions. It was reported that the ZnO-C3N4could be prepared by mixing the powder ZnO with C3N4that was dispersed in methanol, followed by drying process under nitrogen atmospheres. In the present study, a series of ZnO-C3N4was prepared bya simplermethod, which was impregnationof zinc oxide precursor on the C3N4, followed by calcination process. The effect of zinc to carbon ratio (Zn/C) on the properties and photocatalytic activity was examined.XRD patterns of the samples revealed that as the Zn/C ratio increased, the intensity of diffraction peaks for ZnO also increased but the intensity for C3N4 decreased. All the prepared composite materials have an extended absorption band in the visible light region due to the presence of C3N4, as supported by DR-UV Vis spectra. The prepared ZnO-C3N4 composites were further investigated in the photocatalytic removal of phenol under visible light irradiation for 5 hours. All ZnO-C3N4 samples showed higher activity than the bare ZnO (Figure 1). The ZnO-C3N4 with Zn/C ratio of 1 mol% showed the highest photocatalytic activity for removal of phenol among all the samples. The high activity observed on the ZnO-C3N4 would be due to the role of C3N4 to suppress electron-hole recombination and extend the absorption ofZnO in the visible light region.

A series of copper oxide loaded TiO2 was prepared by a photodeposition method. It was clarified through XANES that the added copper species solely existed as highly dispersed Cu(II) and it remained as Cu(II) after the photocatalytic reaction. The prepared CuO/TiO2 with various contents (0.1–5 mol%) were used as photocatalysts for 2,4-dichlorophenoxyacetic acid (2,4-D) degradation under UV, visible, and solar simulator irradiation. Under UV light irradiation, the photocatalytic activity of 2,4-D decomposition increased by a maximum factor of 4.3 compared with unmodified TiO2 when TiO2 was loaded with 0.75 mol% CuO. In contrast, under visible light and solar simulator irradiation, the optimum loading of CuO was much lower (0.1 mol%) and enhancements of 22.5 and 2.4 times higher activities were observed, respectively. These results showed that the different masking effects due to the different light sources led to different optimum amounts of CuO, and the added CuO mostly contributed to the visible light activity of TiO2. Therefore, in addition to the increased charge separation and improved visible light absorption, the masking effect shall also be considered in designing highly active photocatalysts under visible and solar light irradiation.

Titanium dioxide (TiO2) has been recognized as one of the most active photocatalysts for organic pollutant degradation under ultraviolet (UV) light irradiation. In order to reduce the fast charge recombination in the TiO2, various methods have been investigated, including the addition of metal oxide co-catalysts. Owing to the characteristic of the nanoparticles, the modification of nanoparticles involving heat treatment is still a challenging task. In this work, two commercial TiO2 nanoparticles, namely P25 and P90 (Evonik), were modified by copper oxides (CuO) and the photocatalytic activity was evaluated for degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV light. The CuO/P25 and CuO/P90 samples with various loading amounts (0.1, 0.25, 0.5 and 1.0 wt %) were prepared by precipitation of copper(II) nitrate to the P25 or P90 nanoparticles at pH of 9, followed by calcination at 573 K. X-ray diffraction (XRD) patterns indicated that all samples have the characteristics of both anatase and rutile phases. While the addition of CuO did not much affect the structure, crystallite size, and anatase-rutile ratio of the P25 and P90 nanoparticles, the presence of the copper species was confirmed by the scanning electron microscopy (SEM) equipped with the energy-dispersive X-ray (EDX) spectroscopy. Moreover, fluorescence spectra also showed that the CuO quenched the emission intensity of both the P25 and P90 nanoparticles, suggesting the successful decrease of the charge recombination in the TiO2 nanoparticles. Photocatalytic activity tests showed that the P25 and P90 gave percentage degradation of 90 and 47 %, respectively, after a 1-hour reaction. Even though not much improvement was observed for P25 TiO2 nanoparticle after the CuO addition (92 %), the activity of P90 nanoparticle was enhanced from 47 % to 86–87 % with the CuO addition of 0.1–0.25 wt %. This study demonstrated that it is feasible to improve the photocatalytic activity of TiO2 commercial nanoparticles, in this case, the P90, by surface modification using the CuO.

In this study, ZnO material with oxygen defect was successfully synthesized using a hydrothermal method and interestingly, it was found to possess a remarkable photocatalytic activity under the visible light irradiation. The synthesized ZnO material was then characterized using X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible (DR UV-vis), Fourier transform infrared spectroscopy (FTIR), and spectrofluorometer. Both diffraction pattern and absorption spectrum showed the characteristic of ZnO. However, the maximum emission wavelength of the synthesized ZnO was observed at 558 nm, showing that the ZnO was formed with a high concentration of oxygen vacancy. The excitation spectra also indicated that the prepared ZnO could be excited at the visible light region, which was more than 400 nm. The ZnO was evaluated for photocatalytic phenol degradation under UV and visible light. After 15 hours-reaction, the synthesized ZnO showed the ability to degrade 59.8% phenol under UV light and 39.6% phenol under visible light. This result showed a remarkable performance of ZnO under visible light, which was comparable to that performed under UV light. This study proposed that the existence of oxygen vacancy defects successfully induced the photocatalytic activity of ZnO under visible light irradiation through the electron trapping mechanism in the oxygen vacancy state.

Modified gold complexes as dinuclear adducts with silver bridge ions, clusters with other metal ions, and bimetallic sandwiches have shown better sensing capabilities for vapochromic chemosensing of organic vapors than its unmodified structure. Herein, a simple gold(I) complex, synthesized from 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligand, have been shown to have higher sensing capability toward ethanol (EtOH) vapors. Such sensing capability can be possibly achieved when EtOH vapors have enough time to diffuse to the main sensing sites of the sensor. Thus, 80 to 160 µL (with 20 µL increment) of EtOH vapors were exposed to the synthesized gold(I) pyrazolate complex at varied distances of 2.75, 11 and 22 cm for 15 minutes. The complex displayed its sensing capability by quenching at its emission intensity of 600 nm up to 80%, which suggests the possible interaction of the EtOH vapors with the inner sensing site originated from the Au(I)–Au(I) interaction of the complex where it is possible to breakdown the light-emitting capability. Prior to this interaction, there was only a slight blue-shifting of 9 nm away from its emission intensity by the binding of EtOH vapors to the methoxy of benzene ring hence only demonstrating weak sensing capability. These results indicated that sensing capability as shown by the quenching phenomenon at the emission intensity of gold(I) complex is dependent on diffusion time of EtOH vapors.

Ordered carbon (OC) with large surface area was prepared via replication by using Santa Barbara Amorphous-15 as a template and sucrose as a carbon precursor. The prepared OC was then noncovalently functionalized with Basic Red 2 dye precursor (BR2) to obtain OC–BR2, a nitrogen-containing carbon-based nanocomposite with enhanced electrical properties. The functionalization was explained through adsorption isotherm, kinetic, and thermodynamic studies performed under variable conditions. The electrochemical performance test results demonstrated that the nanocomposite presents enhanced capacitance (48.4%) compared with the original OC, with maximum specific capacitance of 227 F g−1 at 0.5 A g−1 in 1 M KOH electrolyte.

In the present study, commercial Hombikat N100 TiO2 that consists of 100% of anatase phase was modified with copper (Cu) as a co-catalyst via two different preparation methods, which were photocatalytic UV reduction and impregnation methods. The Cu loading was fixed to be 0.1 wt%. The X-ray diffraction (XRD) patterns showed that Cu/TiO2 sample prepared via different preparation methods gave different crystallinity and/or crystallite size. The Cu/TiO2 sample prepared by photocatalytic UV reduction method has lower crystallinity and/or crystallite size than the sample prepared by impregnation method. The performance of the TiO2 and Cu/TiO2 samples was evaluated for degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). After 1 hour reaction, the TiO2 showed percentage removal of 31%, while the Cu/TiO2 sample prepared by photocatalytic UV reduction and impregnation methods gave 39 and 28%, respectively. It was proposed that the higher activity on the Cu/TiO2 sample prepared by photocatalytic UV reduction method was caused by the more successful suppression of electron-hole recombination, as supported by the emission spectra.

The fast electron-hole recombination in mesoporous carbon nitride (MCN) photocatalyst has spurred a great interest to improve its efficiency with addition of various modifiers. In the present study, the MCN was modified by reduced graphene oxide (rGO) that was synthesized via a novel photocatalytic reduction method with different ratios of GO to MCN to produce rGO-MCN composites. The synthesized rGO-MCN samples were characterized by X-ray diffractometer (XRD), diffuse reflectance UV-visible (DR UV-Vis), and Fourier transform infrared (FTIR) spectroscopies. It was confirmed that rGO was successfully combined with the MCN without affecting the structure of the MCN. With the higher amount of GO ratio, the composites showed more observable rGO peaks in the IR spectra and higher background absorption in the visible region of DR UV-Vis spectra. The photocatalytic removal of N-nitrosopyrrolidine (NPYR) was carried out at room temperature under visible light irradiation to investigate the photocatalytic efficiency of the composites. The ratio of GO was found to affect the photocatalytic activity of the rGO-MCN composites. The photocatalytic activity of the prepared composites increased with GO loading from 1 to 5 wt.%, owing to the slightly enhanced absorption in visible light as shown in DR UV-Vis spectra and the undisrupted graphitic structure of MCN upon characterizations by XRD and IR spectra. It was found that 5 wt.% was the optimum amount of GO ratio and there was no further improvement in photocatalytic activity when the GO ratio increased.

In order to improve the efficiency of TiO2, material with large surface area such as mesoporous silica is usually used as a support. In this study, the TiO2 was dispersed on mesoporous silica, MCM-41 by an impregnation method, meanwhile the bulk TiO2 was prepared by sol gel method. The X-ray diffraction (XRD) patterns showed that the intensities of diffraction peaks for MCM-41 decreased with the increase of the TiO2 loading, suggesting that the higher loading amount of TiO2 might lead to less ordered structure of MCM-41. The successful addition of TiO2 on MCM-41 was also confirmed from the fluorescence spectra, which the emission intensities of TiO2 and MCM-41 increased and decreased, respectively, with the increase of TiO2 loading on the MCM-41. The activities were compared between the bulk and dispersed TiO2 for photocatalytic oxidation of hexanol. Both bulk and dispersed TiO2 on MCM-41 showed good photocatalytic activity, while the MCM-41 did not show photocatalytic activity. Since the efficiency of photocatalyst can be defined by its respective turnover number (TON), the comparison between bulk and dispersed TiO2 on MCM-41 was made based on their TON values. It was revealed that the dispersed TiO2 on the MCM-41 with 5 wt% of TiO2 loading was the most efficient photocatalyst among all the samples.

Titanium dioxide (TiO2) has been recognized as an active photocatalyst for degradation of various organic pollutants. In this study, in order to improve the photocatalytic activity of TiO2, the effect of lanthanum oxide modification was investigated by using commercial P25 as the benchmark. Lanthanum oxide/P25 TiO2 composites with 0.1, 0.5, 1 and 5 mol% of La loadings were prepared via an impregnation method. The resultant composites were characterized by X-ray diffraction (XRD), UV-Vis absorption spectroscopy, transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and electrochemical impedance spectroscopy (EIS). It was confirmed that the addition of lanthanum oxide did not much affect the crystallinity, crystal structure and the morphology of P25 TiO2. The catalytic activities of the lanthanum oxide/P25 TiO2 catalysts were tested by using 2,4-dichlorophenoxyacetic acid (2,4-D) as the test pollutant and UV light as the irradiation source. The reaction was caried out for 1 hour at room temperature and the percentage removal was determined using a UV spectrophotometer. The results showed that La loading was an important factor that influenced the photocatalytic activity of the composites. After 1 hour reaction, the best catalyst with 0.1 mol% of La loading showed 24% higher photocatalytic activity than the unmodified P25 TiO2 catalyst. It is shown by EIS that the enhanced photocatalytic activity of the composites was due to the ability of lanthanum oxide in improving the charge separation of the photogenerated electron-hole pairs in TiO2.

Microporous aluminophosphate (AlPO-5) and titanium aluminophosphate (TAPO-5) molecular sieves, which are zeolite-like materials have been synthesized by direct hydrothermal method using two different templates; triethylamine (TEA) as organic base and tetraethylammonium hydroxide (TEAOH) as alkali base. XRD patterns confirmed that the TAPO-5 catalysts are identical with AFI structure but the crystallinity of the catalysts had decreased after the incorporation of titanium into the framework. Besides that, characterization of TAPO-5 catalysts using DRUV-Vis confirmed the coordination of titanium species and this evidenced also supported by the result 27Al MAS NMR. Catalytic performance of the TAPO-5 catalysts was tested in the oxidation of styrene to produce benzaldehyde and phenylacetaldehyde in the presence of hydrogen peroxide as oxidant. TAPO-5 catalysts showed higher activity in styrene oxidation compared to AlPO-5. Keywords: zeolite; aluminophosphate; titanium; organic template; styrene

Rare earth (RE) ions play an important role in the improvement of the optical properties of ceramics. Rare-earth ceramics are commonly used in display panels, fluorescent lamps and lasers. The luminescence properties of Magnesium Boro-Tellurite (MBT) Eu3+ and Dy3+ doped ceramics have not been reported before. Therefore, the aim of this paper is to determine the effect of different compositions on the luminescence properties of the MBT material. A series of xTeO2-(70-x)B2O3-30MgO ceramics with 10 ≤ x ≤ 40 mol % doped with 1 mol % of Eu3+ and Dy3+ ions was prepared via the solid-state reaction method. The influence of various compositions on the crystalline phase and photoluminescence properties of the samples were investigated by X-ray diffraction (XRD) and luminescence spectroscopy. The crystalline phases obtained in this study are Mg3(BO3)2, MgB4O7, Mg2B2O5, Mg(Te2O5) and MgTe3O6. It was stated that the crystalline phases have not changed as a result of doping with Eu3+ and Dy3+ ions. The emission spectra of Eu3+: MBT ceramics showed strong red emission at 612 nm due to the transition of 5D0 → 7F2 and meanwhile, the Dy3+: MBT ceramics showed a blue emission at 480 nm due to 4F9/2 → 6H15/2 transition and yellow emission at 576 nm due to 4F9/2→6H13/2 transition. Both the rare-earth doped phosphors showed bright emission.

This article reports on the physical and optical properties, absorption, and luminescence spectra in the visible region, of calcium zinc borophosphate glasses doped with manganese ions. The manganese composition was varied up to 10 mol%. The aim of this work was to investigate the effect of the luminescence properties when the glasses were doped with different compositions of manganese ions. X-ray diffraction profiles confirmed their glassy nature. The optical absorption spectrum showed bands characteristic of manganese ions in octahedral symmetry. Both excitation and emission spectra were recorded for these glasses to understand their optical performances. The emission spectrum showed a single broad band (green region) in octahedral symmetry at 582 nm as a result of transition from the upper 4T1g state to the 6A1g ground state of manganese ions. As the concentration of manganese ions increased, the emission band increased from 582 nm (green-light emission) to 650 nm (red-light emission). Apart from the s...

Development of efficient visible light-driven photocatalysts is an important approach towards sustainability. Herein, reduced graphene oxide–graphitic carbon nitride (rGO–gCN) photocatalysts were successfully prepared by in situ photocatalytic reduction of graphene oxide (GO) in the presence of gCN as the photocatalyst. The XPS spectra revealed the presence of N-graphene, which confirmed the interaction between the rGO and the gCN. The rGO–gCN with GO loading amount of 0.1 wt% exhibited almost three times higher photocatalytic activity than gCN for degradation of phenol under visible light irradiation. Fluorescence spectroscopy, EIS, and photocurrent response studies indicated that the presence of rGO significantly promoted the electron–hole separation and improved the interfacial charge transfer on the gCN. These factors played a crucial role in enhancing the photocatalytic activity of the gCN under visible light irradiation.

Mesoporous carbon nitride (MCN) was used for the first time as a thermal catalyst for the removal of aniline. While bulk carbon nitride (BCN) and mesoporous silica (MCM-41) did not show any catalytic activities, the MCN showed aniline removal (33%) at 398 K. It was revealed that the much higher activity of the MCN originated from the presence of mesoporosity and suitable adsorption sites for the reaction to occur. The nature of aniline adsorption on MCN was found to fit well to the Freundlich adsorption model. The evidence on the interactions between aniline and MCN was supported by fluorescence and FTIR spectroscopies. It was suggested that the interactions between MCN and aniline involved both weak π to π stacking and strong hydrogen bonding, which were important to initiate the catalytic removal of aniline.

We highlight that by using supramolecular single crystals of phosphorescent trinuclear copper(I) pyrazolate complexes with different molecular structures ( 2 A-E ), vapochromic chemosensors were successfully designed for sensing ethanol with high sensing capability. These complexes 2 A-E were synthesized from non-side chain, 3,5-dimethyl, 3,5-bis(trifluoromethyl), 3,5-diphenyl and 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligands ( 1 A-E ) in 83, 97, 99, 88 and 85% yields, respectively. All complexes showed emission bands centered at 553, 584, 570 and 616 nm upon an excitation at 280 nm for complexes 2 A-C,E , respectively and 642 nm upon an excitation at 321 nm for complex 2 D with lifetime in microseconds, indicating a large Stoke shift for phosphorescent compounds. These emission spectra were in good agreement with their colors from green to red upon exposure to a UV lamp with an excitation at 254 nm in dark room. Upon exposure to ethanol in 5 min, quenching, photoinduced energy transfer and shifting of emission intensities were observed for chemosensors 2 A - C , 2 D and 2 E , respectively. Interestingly, chemosensor 2 E only showed completely and autonomously recovery of its original emission intensity. Such novel finding in sensing capability might be caused by a weak intermolecular hydrogen bonding interaction of ethanol to oxygen atoms at dimethoxybenzyl side-chains of the pyrazole ring.

We highlight that columnar assembly of self-assembled templates was successfully utilized using sol-gel technique of mesostructured silica for the quality improvement of transparent mesoporous film nanocomposites with a hexagonal structure through appropriate heat treatment methods and self-assembled templates in the removal of organic components. In contrast to the reported mesostructured silica film nanocomposites containing columnar assembly of trinuclear gold(I) pyrazolate complex ([Au3Pz3]C10TEG/silicahex) with calcination at 450 °C, mesostructured silica film nanocomposites from self-assembled template of triphenylene bearing amphiphilic decoxy triethylene glycol side chains (TPC10TEG/silicahex) can be completely collapsed upon calcination at 450 °C. This hexagonal structure can be only preserved with calcination at 250 °C although intensity of its main diffraction peak of d100 at 2θ of 3.70° was significantly decreased. On the other hands, thermal hydrogen reduction at the same temperature was foun...

In this study, mesoporous carbon nitride (mp-C3N4) was used as a novel removable template to prepare iron (III) oxide (Fe2O3) nanoparticles. Without the template, the formed Fe2O3 has micrometer size, while using the mp-C3N4 template led to the formation of Fe2O3 nanoparticles. The prepared Fe2O3 nanoparticles showed comparable high crystallinity to the Fe2O3 sample prepared without template. It was confirmed that all samples prepared using mp-C3N4 template showed better photocatalytic activity than the bulk Fe2O3. Total removal of phenol (100%) can be achieved after 15 h on the Fe2O3 samples prepared at 973 K using mp-C3N4 with pore sizes of 7 and 12 nm, while only ca. 30% was observed on the bulk Fe2O3. It was suggested that the smaller the particle size, the shorter the diffusion length of electron to migrate to the surface, resulted in the lower electron-hole recombination that would lead to the higher photocatalytic activity.

Eu3+ doped borophosphate glasses with the chemical composition 20Li2O-30Al2O3-10B2O3-40P2O5-xEu2O3 (where x=0.05 mol.%, 0.1 mol.%, 1.0 mol.%, 1.5 mol.% and 2.0 mol.%) were prepared by conventional melt quenching technique. The structural and luminescence properties of the prepared Eu3+ doped borophosphate glasses were studied and compared with reported results. The XRD pattern showed the amorphous nature of the prepared glasses. Whereas, the FTIR spectra revealed the vibrational modes in the prepared glasses. The bonding parameters ( β ¯ and δ) were calculated through the excitation spectra. Judd–Ofelt (J–O) intensity parameters were calculated from the emission spectra and were used to determine transition probability (A), stimulated emission cross-section (σEP), radiative lifetime (τR) and branching ratios (βexp) for the transition 5D0→7Fj (j=1, 2, 3 and 4) of Eu3+ ions. Furthermore, the luminescence intensity ratio (R) of 5D0→7F2 to 5D0→7F1 transition was also calculated. Transition 5D0→7F2 had the highest value of stimulated emission cross-section and branching ratios and the results were comparable with the reported values. This indicated that the present glass is promising host material for Eu3+ doped fiber amplifiers.

In the present study, carbon-coated titanium oxide (C-TiO2) was synthesized by hydrothermal method using dichloromethane as the novel low-cost carbon source. XRD patterns revealed that after purification method, only diffraction peaks of anatase TiO2 can be observed. On the other hand, the formation of carbon can be suggested from DR UV-visible spectrum and SEM image, which showed the additional of absorption band in the visible region and the successful formation of carbon that grew both on the surface with a unique noodle-like structure and surroundings of the TiO2 with non-uniform bulk structure, respectively.

Here chemosensor materials of trinuclear copper (I) pyrazolate complexes have been successfully synthesized and isolated using two types of 3,5-dimethyl and 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligands. Upon excitation at 280 nm, the resulting trinuclear 3,5-dimethyl copper (I) pyrazolate complex (complex A) and trinuclear 4-(3,5-dimethoxybenzyl) copper (I) pyrazolate complex (complex B) showed emission bands centered at 590 and 604 nm, respectively. These results were in good agreement with their greenish-white powders and it is characteristic of phosphorescent metal complexes from the weak Cu (I)-Cu (I) metallophilic interaction. Upon direct or stepwise exposure to ethanol vapor with series of concentrations (12.5, 25, 50, 100, 150 and 200μL in 22 mg of chemosensor), the emission of chemosensor complex A was not shifted even after 1 d. Interestingly, chemosensor complex B showed gradually changes in both emission band with shifting from 602 to 552 nm and color with changing from orange to green under Ultra-violet (UV) hand lamp (254 nm) at the dark room due to the attachment of benzyl ring to the pyrazole ligand. This positive response for chemosensor complex B was reversible; hence, this optical phosphorescent material can be used for developing vapochromic sensors of ethanol.

Calcium zinc borophosphate glasses (CaZnBP) doped with various concentrations of Mn 2+ ions and borate and phosphate as variable were prepared using conventional melt quenching technique. The structure of obtained glasses were examined by means of use: X-ray diffraction (XRD) and fourier transform infrared (FT-IR). XRD analysis confirmed amorphous nature of glass samples. The FT-IR spectra reveals the presence of both borate and phosphate vibrational modes in the prepared glasses. The doping of Mn 2+ ions (2–10 mol%) shows no significant changes in the main IR vibrational bands. Optical properties were studied by measuring the near infrared photoluminescence (PL) spectra. CaZnBP glasses exhibited intense green emission peak (582 nm) (tetrahedral symmetry), which is assigned to a transition from the upper 4 T 1g → 6 A 1g ground state of Mn 2+ ions. As the concentration of Mn 2+ ions increases, the emission band increases from 582 nm to 650 nm and exhibited a red light emission (octahedral symmetry). The decay curves of 4 T 1g level were examined for all concentrations and the measured lifetimes are found to depend strongly on Mn 2+ concentrations. From the emission characteristic parameters of 6 A 1g (S) level, it shows that the CaZnBP glasses could have potential applications as luminescent optical materials, visible lasers and fluorescent display devices.

Aniline is a toxic organic pollutant that is abundantly present in the environment. One of approaches to remove the aniline is by adsorption process. In this study, mesoporous carbon nitride (MCN) was proposed for the first time to be a potential adsorbent for aniline. The adsorption studies were carried out at room temperature on the aniline solution with various initial concentrations for both bulk carbon nitride (BCN) and MCN. Owing to its larger surface area, the MCN showed much higher adsorption capacity towards aniline compared to the BCN. This result indicated that adsorbent with large surface area is very crucial in the adsorption of aniline. Comparison study was also carried out using mesoporous silica, MCM-41, which was reported to act as a good adsorbent for aniline. The adsorption capability of MCN was found to be higher than that of MCM-41. It was suggested that the MCN with larger pore diameter might have more suitable and favourable adsorption sites for aniline compared to MCM-41. This study obviously showed that MCN would be a new potential adsorbent for removal of aniline.