Optimization of Extraction Conditions from Gac Fruit and Utilization of Peel-Derived Biochar for Crystal Violet Dye Removal.

Gac fruit (Momordica cochinchinensis Spreng.) is a prominent source of carotenoids, renowned for its exceptional concentration of these compounds. This study focuses on optimizing the extraction of active components from the aril of gac fruit by evaluating the effects of extraction temperature, solid-liquid ratio, and extraction time. The primary objective is to maximize the yield of gac oil while assessing its antioxidant capacity. To analyze the kinetics of the solid-liquid extraction process, both first-order and second-order kinetic models were employed, with the second-order model providing the best fit for the experimental data. In addition, the potential of gac fruit peel as a precursor for biochar production was investigated through carbonization. The resultant biochars were evaluated for their efficacy in adsorbing crystal violet (CV) dye from aqueous solutions. The adsorption efficiency of the biochars was found to be dependent on the carbonization temperature, with the highest efficiency observed for BCMC550 (91.72%), followed by BCM450 (81.35%), BCMC350 (78.35%), and BCMC250 (54.43%). The adsorption isotherm data conformed well to the Langmuir isotherm model, indicating monolayer adsorption behavior. Moreover, the adsorption kinetics were best described by the pseudo-second-order model. These findings underscore the potential of gac fruit and its byproducts for diverse industrial and environmental applications, highlighting the dual benefits of optimizing gac oil extraction and utilizing the peel for effective dye removal.

Food waste and soybean curd residue composting by black soldier fly.

This study attempted to manage the food waste and soybean curd residue generated in Taiwan's National Ilan University by black soldier fly-aided co-composting. The food waste and soybean curd residue were co-composted with rice husk as a bulking agent in 4:1 ratio and 0.42 mg BSF/g waste. The higher organic matter degradation of 31.9% was found in Container B (black soldier flies aided food waste and rice husk co-composting) with a rate constant of 0.14 d-1. In Container D (black soldier flies aided soybean curd residue and rice husk co-composting), the organic matter degradation of 29.4% was found with a rate constant of 0.29 d-1. The matured compost of 6.02 kg was obtained from 20 kg of food waste, while 5.83 kg of matured compost was generated from 20 kg of soybean curd residue. The physico-chemical parameters of the final matured compost were in the favorable range of Taiwan's compost standards. The germination index was 188.6% and 194.78% in Containers B and D, respectively. The present study will expand the application of BSF at the institutional level which prove to be a feasible solution for rapid, clean, and efficient composting of post-consumer food wastes.

Preparation of Fe-SBC from Urban Sludge for Organic and Inorganic Arsenic Removal.

In the process of water treatment adsorption has been proved to be the best, because of its significant advantages. It is recognized that recycling and reuse of waste can result in significant savings in materials cost. In this research, the adsorption of organic and inorganic arsenic using sludge biochar (SBC) made from urban sludge were analyzed. The sludge was carbonized using calciner carbonization and then chemically activated at high temperatures and a newly designed Fe-doped sludge biochar (Fe-SBC) presents effective As adsorption in water. Results show that the surface area and average pore volume of Fe-SBC are 498 m² g-1 and 0.33 cm³ g-1, respectively. The adsorption capacity of p-ASA, As(V) and As(III) on Fe-SBC was calculated as 5.47, 3.83 and 3.24 mg L-1, respectively. The adsorption capacity of As were obviously decreased in presence of PO3-4. After six times recycles of adsorption-desorption processes, the adsorption capacity of p-ASA, As(V) and As(III) on Fe-SBC obvious reduction.

Preparation of Zn-Doped Amino Functionalized Biochar from Hazardous Waste for Arsenic Removal.

The utilization of sludge from Far Eastern Memorial hospital (New Taipei city, Taiwan) wastewater treatment plants as biochar adsorbent was investigated. The sludge was carbonized using microwave carbonization and then chemically activated at high temperatures by using ZnCl2 to enhance porosity and surface area. A newly designed Zndoped amino-functionalized sludge biochar (Zn-SBC-DETA) presents effective As adsorption in water. The adsorbent was characterized by nitrogen adsorption-desorption, scanning electron microscopy (SEM) and thermogravimetric analysis. Results show that the surface area and average pore volume of Zn-SBC-DETA are 525 m² g-1 and 0.35 cm³ g-1, respectively. SEM results reveal that Zn-SBC-DETA has uniform pore size. The highest adsorption efficiency of As(III) is 79% at pH 3 with an adsorption capacity of 0.84 mg g-1. In addition, the adsorption efficiency of As(V) is 98% at pH 3 with an adsorption capacity of 1.43 mg g-1. The adsorption data can be described well by the Langmuir model rather than by the Freundlich model The data show good compliance with the pseudo second-order equation, and the correlation coefficient for the linear plots is higher than 0.97. Combined with the As species after reacting with Zn-SBC-DETA, the As transformation and adsorption mechanism are also discussed.

Photocatalytic Degradation of Oxytetracycline by Ternary Mixed Catalyst and Toxicity Assessment Using Boar Sperm.

Response surface methodology was adopted to obtain ternary mixed catalysts of TiO2-loaded ZSM-5 zeolite and graphene. Oxytetracycline was used as challenged toxicant to evaluate the photocatalytic degradation efficiency of the composites. The optimal weight ratio of graphene, TiO2, and ZSM-5 was 1:8:1. The composites were characterized by ultraviolet-visible spectroscopy, X-ray diffraction, fourier transform infrared, N2 adsorption-desorption isotherms, and transmission electron microscope with an energy-dispersive spectroscopy system, etc. Synthesized samples showed high stability and strong visible-light absorption efficiency. The optimal operating conditions of oxytetracycline photocatalytic degradation were achieved over a wide range of pH and temperature. With 0.1 g/L of optimal ternary mixed composite, the photocatalytic degradation of oxytetracycline was nearly reached completion within 150 min at all treatment temperatures at pH 7. Toxicity of degraded oxytetracycline solution was assayed by a boar sperm quality model using fluorescent staining and flow cytometry. During 180 min of photocatalytic treatment, the degraded oxytetracycline solution showed increasing biotoxicity and changed the morphology and function of boar sperm, despite not killing them.

Preparation and Photocatalytic Hydrogen Production of Pt-Graphene/TiO2 Composites from Water Splitting.

Hydrogen is considered as a promising energy source with its high energy yield, renewable, environment friendly properties. TiO2 modified with noble metal and nonmetal is widely used. In this study, Pt and graphene (GN) were used to modify TiO2 nanoparticles. GN/TiO2 (TG), Pt-TiO2 (PT), Pt-GN/TiO2 (PTG) was successfully synthesized by modified Hummers' method, alcohol thermal and photodeposition method, respectively. The characterizations of the synthesized catalysts by UV-vis/DRS, components analysis, XRD and TEM analysis were conducted. Results showed the maximum hydrogen production rate was approximately 4.71 mmol h-1 g-1 when the Pt content was 1.0 wt.%. Higher and lower than 1.0 wt.% of Pt loading content both result in low efficiency of hydrogen production. The situation of graphene is similar to Pt. The optimal ratio for grapheme is 10 wt.%. The highest hydrogen production rate is 6.58 mmol h-1 g-1 by 1.5 wt.% Pt-5 wt.% GN/TiO2 (1.5PTG5), which is about 1.4 and 2.2 times higher than that of Pt-TiO2 and GN/TiO2 binary composites, respectively. The utilization of low-cost graphene can reduce the use of noble metal Pt in photocatalytic hydrogen production. The mechanism of Pt-GN/TiO2 for the improved photocatalytic activity is proposed. 0.1 g L-1 is found to be the optimum catalyst concentration for optimal hydrogen production.

Triangular Silver Nanoplate-Coated ZnO Nanoflowers Photocatalysis of Norfloxacin Under Visible Light.

T-Ag/ZnO nanoflowers were successfully fabricated via two steps methods on zinc foil. The chemical composition of norfloxacin was investigated by FTIR spectroscopy. The morphology, composition, and structural and optical properties of the as-synthesized materials were characterized. The results show that triangular silver nanoplates exhibit unique surface plasmon resonance (SPR) absorption spectra, and the absorption spectrum range of ZnO nanoflowers are effectively expanded by coating triangular silver nanoplates. The photocatalytic degradation of norfloxacin activity can be obviously improved because of a synergetic effect and unique SPR of triangular silver nanoplates in the T-Ag/ZnO nanoflowers under visible light. In addition, the possible mechanism for T-Ag/ZnO nanoflowers for the photodegradation of norfloxacin are discussed. The stability of T-Ag/ZnO nanoflowers are also studied.

Hexamethyldisilazane Removal with Mesoporous Materials Prepared from Calcium Fluoride Sludge.

A large amount of calcium fluoride sludge is generated by the semiconductor industry every year. It also requires a high amount of fuel consumption using rotor concentrators and thermal oxidizers to treat VOCs. The mesoporous adsorbent prepared by calcium fluoride sludge was used for VOCs treatment. The semiconductor industry employs HMDS to promote the adhesion of photo-resistant material to oxide(s) due to the formation of silicon dioxide, which blocks porous adsorbents. The adsorption of HMDS (Hexamethyldisiloxane) was tested with mesoporous silica materials synthesized from calcium fluoride (CF-MCM). The resulting samples were characterized by XRD, XRF, FTIR, N2-adsorption-desorption techniques. The prepared samples possessed high specific surface area, large pore volume and large pore diameter. The crystal patterns of CF-MCM were similar with Mobil composite matter (MCM-41) from TEM image. The adsorption capacity of HMDS with CF-MCM was 40 and 80 mg g-1, respectively, under 100 and 500 ppm HMDS. The effects of operation parameters, such as contact time and mixture concentration, on the performance of CF-MCM were also discussed in this study.

Effects of Different Sacrificial Agents and Hydrogen Production from Wastewater by Pt-Graphene/TiO2.

The Pt and graphene (GN) were used to modify TiO2 nanoparticles. GN/TiO2, Pt-TiO2, Pt-GN/TiO2 were successfully synthesized by modified Hummers' method, alcohol thermal and photodeposition method, respectively. The characterizations of the synthesized catalysts by different characterization techniques, including N2 adsorption-desorption isotherm, fourier transform infrared spectroscopy (FTIR), inductively coupled plasma (ICP) technique and element analyzer (EA), respectively. In addition, different sacrificial agents (methanol, ethanol, n-propanol, i-propanol, n-butanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol and glycerol) have been investigated. There is clearly a linear relationship between hydrogen production rate and the polarity of monohydric alcohols. According to the Langmuir-Hinshelwood results, the surface pseudo-first order rate constant k = 15.06 mmol h-1 g-1 and the adsorption coefficient k = 0.50 mol L-1 were obtained. The feasibility of hydrogen production from wastewater obtained from terephthalic acid industry was studied. After reusing the catalyst under the same experimental conditions, the hydrogen production rate has only slightly decreased for 3 more cycles, which indicated the stability of the synthesized catalysts.

Preparation of Zn-Doped Biochar from Sewage Sludge for Chromium Ion Removal.

Recycling and reuse waste can result in significant savings in materials and energy. In this study, the adsorption of Cr(VI) was analyzed using activated carbon (AC) and biochar (BSC) made from sewage sludge. BSC materials were synthesized using zinc chloride as an activator coupled with carbonized sewage sludge. Specific surface area, pore size distribution, and pore volume were determined by measuring nitrogen adsorption-desorption (BET). BSC morphology was measured using field-emission scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). Results showed that the surface area and average pore volume of the BSC were 490 m2 g-1 and 0.8 cm3 g-1, respectively. SEM results revealed that BSC had uniform pore size. Effects of varying the initial Cr(VI) concentrations, pH values, and dosages of BSC on adsorption performance were also determined. Results showed that the maximum removal efficiency of Cr(VI) was above 99%, and adsorption capacity of 50% ZnCl2-BSC was 677 mg g-1.

Removal of ammonium and heavy metals by cost-effective zeolite synthesized from waste quartz sand and calcium fluoride sludge.

This study focuses on the effectiveness of zeolite (10% CF-Z [0.5]) hydrothermally synthesized from waste quartz sand and calcium fluoride (CF) for ammonium ion and heavy metal removal. Zeolite was characterized through powder X-ray diffraction, Fourier-transform infrared spectroscopy, micromeritics N2 adsorption/desorption analysis, and field emission scanning electron microscopy. The effects of CF addition, Si/Al ratio, initial ammonium concentration, solution pH, and temperature on the adsorption of ammonium on 10% CF-Z (0.5) were further examined. Results showed that 10% CF-Z (0.5) was a single-phase zeolite A with cubic-shaped crystals and 10% CF-Z (0.5) efficiently adsorbs ammonium and heavy metals. For instance, 91% ammonium (10 mg L-1) and 93% lead (10 mg L-1) are removed. The adsorption isotherm, kinetics, and thermodynamics of ammonium adsorption on 10% CF-Z (0.5) were also theoretically analyzed. The adsorption isotherm of ammonium and lead on 10% CF-Z (0.5) in single systems indicated that Freundlich model provides the best fit for the equilibrium data, whereas pseudo-second-order model best describes the adsorption kinetics. The adsorption degree of ions on 10% CF-Z (0.5) in mixed systems exhibits the following pattern: lead > ammonium > cadmium > chromium.

Acetones Removal with Fe Doped Titanium Nano Tube Catalysts Prepared from Slag Iron in Steel Plant.

TiO2 has been studied most commonly because it has high stability, non-toxicity, high catalytic activity, and highly conductivity. Many studies have shown that TiO2 would generate electron-hole pairs illuminated with UV and surround more energy than that before being illuminated. However, the surface area of TiO2 is not large enough and the adsorption capacity is small. In this study, the titanium nano tube (TNT) catalysts were prepared to increase the surface area and adsorption capacity. The Fe-TNT was also prepared from slag iron since many slag iron cause waste treatment problems. In this study, the effect of Fe loading, including 0.77%, 1.13%, 2.24% and 4.50%, on acetone removal was also assessed since TNT doped with transitional or precious metals can be used to improve catalytic reaction efficiency. Furthermore, four kinds of VOCs concentration, including 250, 500, 1000 and 1500 ppm were tested. Four kinds of retention time, including 0.4, 0.8, 4.0 and 6.0 sec, and four kinds of dosage, including 0.15, 0.25, 0.30 and 0.45 g cm⁻³, were also assessed. In this study, the adsorption capacity of Fe-TNT was 18.8, 23.3, 28.9 and 32.6 mg g⁻¹ for acetone of 250, 500, 1000 and 1500 ppm, respectively. Four kinds of temperature, including 150, 200, 250 and 300 °C were tested in catalytic reaction system. The results showed removal efficiency increased with increasing temperature. The efficiency can be reached 95% under the conditions with the dosage higher than 0.3 g cm⁻³, temperature higher than 270 °C and retention time higher than 270 °C. Reaction efficiency was 20, 31, 41 and 96% at the temperature of 150, 200, 250 and 300 °C, respectively.

Adsorption of Methyl Blue on Mesoporous Materials Using Rice Husk Ash as Silica Source.

It is recognized that recycling and reuse of waste can result in significant savings in materials and energy. In this research, the adsorption of methyl blue (MB) using waste rice husk ash (Rha) and mesoporous silica materials made from Rha (R-MCM) were analyzed. Mesoporous silica materials were synthesized using cetyltrimethyl ammonium bromide (CTAB) as a cationic surfactant and Rha as the silica source. The prepared samples were characterized by Brunnaur-Emmet-Teller (BET) adsorption isotherm analyzer and transmission electron microscope (TEM) analysis. The results showed the surface area of R-MCM materials was 1347 m2g-1 and the pore volume was 0.906 cm3g-1. TEM analysis showed that the mesoporous materials generally exhibited ordered hexagonal arrays of mesopores with a uniform pore size. The effects on adsorption performance under different initial dye concentrations, different pH values and different dosages of adsorbent were also studied. Both Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. The results show that the maximum removal efficiency of MB more than 99%.

Deciphering visible light photoreductive conversion of CO2 to formic acid and methanol using waste prepared material.

As gradual increases in atmospheric CO2 and depletion of fossil fuels have raised considerable public concern in recent decades, utilizing the unlimited solar energy to convert CO2 to fuels (e.g., formic acid and methanol) apparently could simultaneously resolve these issues for sustainable development. However, due to the complicated characteristics of CO2 reduction, the mechanism has yet to be disclosed. To clarify the postulated pathway as mentioned in the literature, the technique of electron paramagnetic resonance (ESR) was implemented herein to confirm the mechanism and related pathways of CO2 reduction under visible light using graphene-TiO2 as catalyst. The findings indicated that CO(-•) radicals, as the main intermediates, were first detected herein to react with several hydrogen ions and electrons for the formation of CH3OH. For example, the generation of CO(-•) radicals is possibly the vital rate-controlling step for conversion of CO2 to methanol as hypothesized elsewhere. The kinetics behind the proposed mechanism was also determined in this study. The mechanism and kinetics could provide the in-depth understanding to the pathway of CO2 reduction and disclose system optimization of maximal conversion for further application.

Preparation of 13X from Waste Quartz and Photocatalytic Reaction of Methyl Orange on TiO2/ZSM-5, 13X and Y-Zeolite.

TiO2 photocatalytic reactions not only remove a variety of organic pollutants via complete mineralization, but also destroy the bacterial cell wall and cell membrane, thus playing an important bactericidal role. However, the post-filtration procedures to separate nanometer-levels of TiO2 and the gradual inactivity of photocatalyst during continuous use are defects that limit its application. In this case, we propose loading TiO2 on zeolite for easy separation and 13X is considered as a promising one. In our study, 13X-zeolite was prepared by a hydrothermal method and the source of Si was extracted from waste quartz sand. For comparison, commercial zeolite with different microporous and mesoporous diameters (ZSM-5 and Y-zeolites) were also used as TiO2 supports. The pore size of the three kinds of zeolites are as follows: Y-zeolite > 13X > ZSM-5. Different TiO2 loading content over ZSM-5, 13X and Y-zeolite were prepared by the sol-gel method. XRD, FTIR, BET, UV-vis, TGA and SEM were used for investigation of material characteristics. In addition, the efficiencies of mineralization and photodegradation were studied in this paper. The effects of the loading ratio of TiO2 over zeolites, initial pH, and concentration on photocatalytic performance are investigated. The relationship between best loading content of TiO2 and pore size of the zeolite was studied. The possible roles of the ZSM-5, 13X-zeolites and Y-zeolites support on the reactions and the possible mechanisms of effects were also explored. The best loading content of TiO2 over ZSM-5, 13X and Y-zeolite was found to be 50 wt%, 12.5 wt% and 7 wt%, respectively. The optimum pH condition is 3 with TiO2 over ZSM-5, 13X-zeolites and Y-zeolites. The results showed that the degradation and mineralization efficiency of 12.5 wt%GT13X (TiO2 over 13X) after 90 min irradiation reached 57.9% and 22.0%, which was better than that of 7 wt%GTYZ (TiO2 over Y-zeolites) while much lower than that of 50 wt%GTZ (TiO2 over ZSM-5). The materials were recycled four times while the degradation was remained at a higher level.

Photocatalytic degradation of reactive red 141 in the presence of Cr(VI) using TiO2 nanotubes.

TiO2 nanotubes were prepared by hydrothermal process, then characterized using Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-Visible spectroscopy measurements. The photodegradation performance assessment of Reactive Red 141 (RR141) with near visible light irradiation (lambda = 380 nm) was carried out under different catalyst doses, dye concentrations, pH and initial Cr(VI) concentrations by TiO2 powder and nanotubes. The results showed that the specific surface area of TiO2 nanotubes were 152 m2 g(-1), about three times larger than that of TiO2 powder which was roughly 51 m2 g(-1). The TiO2 nanotubes did not affect the lattice structure of the TiO2. The adsorption amount increases as the dosage and RR141 concentration increases. However, the decolonization efficiency decreased with increasing initial RR141 concentration. Results also showed that an acidic solution is more favorable for photocatalytic degradation of RR141. On the other hand, Cr(VI) can be adsorbed on the surface of TiO2 nanotubes to affect the decolonization efficiency of RR141.

Catalytic decomposition of CF4 over iron promoted mesoporous catalysts.

A series of mesoporous catalysts (MCM-41) promoted by iron nanoparticles were prepared by the co-precipitation method and tested for the decomposition of carbon tetrafluoride (CF4). The addition of iron oxide nanoparticles to MCM-41 led to an improvement in the catalytic activity for CF4 decomposition. The catalyst was the most active around 5 wt% iron added to MCM-41. Methods of X-ray Powder Diffractometer, Scanning Electron Microscope-Energy Dispersive Spectrometer, BET, and high resolution transmission electron microscopy were used to characterize the MCM-41 catalysts. The analytical results indicated that the addition of over 2 wt% iron nanoparticles increased the surface area of MCM-41, which was the rate-determining factor of CF4 decomposition over MCM-41 catalyst. In conclusion, the addition of iron was responsible for the enhancement of catalytic activity of MCM-41.

Study on the methylene blue adsorption from wastewaters by pore-expanded calcium fluoride sludge adsorbent.

The adsorption of methylene blue (MB) onto pore-expanded calcium fluoride sludge (ECF) by the batch adsorption technique was investigated. The results showed that the adsorption capacity increased with increasing MB concentration but decreased as pH was increased. In order to investigate the adsorption mechanisms, three simplified isotherm models and kinetic models were used in this study. The best-fit adsorption isotherm was achieved with the Temkin model. Furthermore, the pseudo-second-order kinetic model agreed very well with the dynamical behavior for the adsorption of MB onto ECF. Thermodynamic studies revealed that the adsorption process of MB onto ECF was spontaneous and exothermic. The results indicated that ECF adsorbed MB efficiently and could be used as a waste adsorbent for the removal of cationic dyes in wastewater treatment.

Study on the degradation of the dye wastewater with polyaniline on titanium nanotubes.

Polyaniline/titanium nanotube composite (PANI/TNT) photocatalysts were prepared by 'in situ'chemical oxidative polymerization of aniline. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform IR spectra (FTIR) and UV-Visible spectroscopy measurements were used to characterize the obtained photocatalysts, and their photocatalytic activities were investigated by degrading Reactive Green19 (RG19) under near visible light irradiation (lambda = 365 nm). The content of PANI, pH, dosage, and concentration of RG19 were also investigated. The results showed that the inner diameter of the PANI/TNT was 6 nm and that the PANI did not change the structure of the TNT. The PANI was coated on the surface of the TNT. The light response of the PANI/TNT was extended to the visible-light regions. Among the six different kinds of photocatalysts, the 1.17 wt% PANI/TNT had the best performance in treating 10 ppm RG19. The best pH is 3 for the largely protonated surface of the composite at low pH. The adsorption amount was increased as the dosage increased. The decolonization efficiency decreased with increasing initial RG19 concentration. The performance of the photocatalyst in decomposing RG19 was stable after 5 time cycles.

Adsorption characterization of gaseous volatile organic compound on mesoporous silica particles prepared from spent diatomaceous earth.

This study used spent diatomaceous earth (SDE) from drink processing as source of Si and cationic surfactant (CTAB) as a template for the synthesis of mesoporous silica Materials (MSM) through hydrothermal method. The MSM was characterized by Small-angle X-ray Diffraction (SXRD), Scanning Electron Microscopy (SEM), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR) spectroscopy and N2 adsorption-desorption analyzer. The results showed that the surface area, pore volume and pore size was roughly ranged from 880 to 1060 m2 g(-1), 1.05 cm3 g(-1) and 4.0 nm, respectively. The properties of the synthesized MSM were also compared with those prepared from pure silica sources (MCM-41) and got almost the same characteristics. The synthesized MSM was used as adsorbent at 25 degrees C with carrier gas of air. The adsorption equilibrium revealed that adsorption capacity of MSM was 59.6, 65.7, 69.6, 84.9 mg g(-1) while the acetone concentration was 600, 800, 1000 ppm, 1600 ppm respectively. Results showed that breakthrough curves correlate to the challenge vapor concentration, adsorbent loading, and the flow rate. The results obtained in the present work demonstrated that it was feasibility of using the SDE as a potential source of silica to prepare MSM.