scholarly journals Photocatalytic Pretreatment of Commercial Lignin Using TiO2-ZnO Nanocomposite-Derived Advanced Oxidation Processes for Methane Production Synergy in Lab Scale Continuous Reactors

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 54
Author(s):  
Yu-Ming Chu ◽  
Hafiz Muhammad Asif Javed ◽  
Muhammad Awais ◽  
Muhammad Ijaz Khan ◽  
Sana Shafqat ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Advanced Oxidation Processes ◽  
Synergistic Effects ◽  
Oxidation Products ◽  
Methane Yield ◽  
Zno Nanoparticle ◽  
Coumaric Acid ◽  
Stirred Tank Reactors ◽  
Lignin Oxidation ◽  
Constant Operation

The photocatalytic pretreatment of lignocellulosic biomass to oxidize lignin and increase biomass stability has gained attention during the last few years. Conventional pretreatment methods are limited by the fact that they are expensive, non-renewable and contaminate the anaerobic digestate later on. The present study was focused to develop a metal-derived photocatalyst that can work with visible electromagnetic spectra light and oxidize commercial lignin liquor. During this project the advanced photocatalytic oxidation of lignin was achieved by using a quartz cube tungsten T3 Halogen 100 W lamp with a laboratory manufactured TiO2-ZnO nanoparticle (nanocomposite) in a self-designed apparatus. The products of lignin oxidation were confirmed to be vanillic acid (9.71 ± 0.23 mg/L), ferrulic acid (7.34 ± 0.16 mg/L), benzoic acid (6.12 ± 0.17 mg/L) and p-coumaric acid (3.80 ± 0.13 mg/L). These all products corresponded to 85% of the lignin oxidation products that were detectable, which is significantly more than any previously reported lignin pretreatment with even more intensity. Furthermore, all the pretreatment samples were supplemented in the form of feedstock diluent in uniformly operating continuously stirred tank reactors (CSTRs). The results of pretreatment revealed 85% lignin oxidation and later on these products did not hinder the CSTR performance at any stage. Moreover, the synergistic effects of pretreated lignin diluent were seen that resulted in 39% significant increase in the methane yield of the CSTR with constant operation. Finally, the visible light and nanoparticles alone could not pretreat lignin and when used as diluent, halted and reduced the methane yield by 37% during 4th HRT.

scholarly journals Synergistic Effects of Multiple Environmental Factors on Degradation of Hydrogenated Nitrile Rubber Seals

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 897 ◽  
Author(s):  
Weitao Lou ◽  
Weifang Zhang ◽  
Tingzhu Jin ◽  
Xuerong Liu ◽  
Wei Dai
Keyword(s):  
Environmental Factors ◽  
Elevated Temperatures ◽  
Synergistic Effects ◽  
Degradation Process ◽  
Nitrile Rubber ◽  
Oxidation Products ◽  
Compression Stress ◽  
Hydraulic Systems ◽  
Hydraulic Oil ◽  
Higher Temperature

Degradation tests of hydrogenated nitrile rubber seals, often used as sealing components in hydraulic systems, were conducted under the free and compression state in air and hydraulic oil at three elevated temperatures for several days to investigate the synergistic effects among three factors. The crosslinking and chain scission reactions both occurred simultaneously at higher temperature during the degradation process, and crosslinking predominated for most cases. Additionally, the synergistic effect between compression stress and hydraulic oil further slowed the degradation rate by limiting oxygen access. However, the higher temperature and hydraulic oil both promoted the formation of oxidation products, whereas the compression stress restrained the formation of amide groups. The fracture morphology results show that the defects gradually formed on the fracture surface, especially for the uncompressed specimens. The increase of the compression set aged in air was more than that in hydraulic oil, implying the more serious degradation. Moreover, rubber seals under the synthetic effect of three environmental factors presented the minimum degradation level. The degradation of the compressed and uncompressed specimens exposed to hydraulic oil is more serious than that of specimens exposed to air.

scholarly journals Photocatalytic Decomposition of Gaseous HCHO over Ag Modified TiO2 Nanosheets at Ambient Temperature

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 338 ◽  
Author(s):  
Xueding Jiang ◽  
Weicheng Xu ◽  
Lian Yu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Oxidation ◽  
Synergistic Effects ◽  
Resonance Effect ◽  
Light Response ◽  
Photocatalytic Decomposition ◽  
Metallic State ◽  
Ag Nps ◽  
Tio2 Nanosheets

Ag nanoparticles loaded onto TiO2 nanosheets with exposed {001} facets were synthesized by solvothermal hydrolysis and photoreduction deposition methods. The results suggested that Ag NPs were uniformly dispersed on the surface of anatase TiO2 NSs with a metallic state. The Raman scattering and visible light absorption performances of Ag/TiO2 NSs were enhanced by Ag NPs due to their surface plasmon resonance effect. Photocatalytic oxidation experiments for HCHO were carried out under visible light, and the enhanced photocatalytic activity of Ag/TiO2 NSs can be attributed to the synergistic effects of the following factors: (1) the {001} facets, which possessed higher surface energy, showed higher photocatalytic activity; (2) the Ag NPs, the increased oxygen vacancies, and O2 adsorption on {001} facets can trap photoelectrons, thus inhibiting the recombination of photoelectrons and holes; (3) the Ag NPs can extend the light response range of TiO2 into visible light. The in situ FTIR results showed that higher mineralization efficiency of HCHO was achieved on Ag/TiO2 NSs than on Ag/TiO2 NPs. Additionally, the mechanism for HCHO photocatalytic oxidation was also discussed.

scholarly journals Combining the Photocatalysis and Absorption Properties of Core-Shell Cu-BTC@TiO2 Microspheres: Highly Efficient Desulfurization of Thiophenic Compounds from Fuel

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2209 ◽  
Author(s):  
Jing Liu ◽  
Xiao-Min Li ◽  
Jing He ◽  
Lu-Ying Wang ◽  
Jian-Du Lei
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Sulfur Removal ◽  
Oxidation Products ◽  
Core Shell ◽  
Adsorptive Desulfurization ◽  
X Ray ◽  
Tio2 Microspheres

A core-shell Cu-benzene-1,3,5-tricarboxylic acid (Cu-BTC)@TiO2 was successfully synthesized for photocatalysis-assisted adsorptive desulfurization to improve adsorptive desulfurization (ADS) performance. Under ultraviolet (UV) light irradiation, the TiO2 shell on the surface of Cu-BTC achieved photocatalytic oxidation of thiophenic S-compounds, and the Cu-BTC core adsorbed the oxidation products (sulfoxides and sulfones). The photocatalyst and adsorbent were combined using a distinct core-shell structure. The morphology and structure of the fabricated Cu-BTC@TiO2 microspheres were verified by scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, X-ray powder diffraction, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy analyses. A potential formation mechanism of Cu-BTC@TiO2 is proposed based on complementary experiments. The sulfur removal efficiency of the microspheres was evaluated by selective adsorption of benzothiophene (BT) and dibenzothiophene (DBT) from a model fuel with a sulfur concentration of 1000 ppmw. Within a reaction time of 20 min, the BT and DBT conversion reached 86% and 95%, respectively, and achieved ADS capacities of 63.76 and 59.39 mg/g, respectively. The BT conversion and DBT conversion obtained using Cu-BTC@TiO2 was 6.5 and 4.6 times higher, respectively, than that obtained using Cu-BTC. A desulfurization mechanism was proposed, the interaction between thiophenic sulfur compounds and Cu-BTC@TiO2 microspheres was discussed, and the kinetic behavior was analyzed.

Effects of Co-Substrates and Mixing Ratio on the Anaerobic Digestion of Navel Orange Waste

2014 ◽  
Vol 878 ◽  
pp. 473-480 ◽  
Author(s):  
Jin Rong Qiu ◽  
Yun Long Fu ◽  
Qing Yun Liu ◽  
Shun Yi Li ◽  
Hai Jun Peng ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Synergistic Effects ◽  
Swine Manure ◽  
Methane Yield ◽  
Navel Orange ◽  
Mixing Ratio ◽  
High Concentration ◽  
Active Sludge ◽  
Promising Alternative ◽  
Orange Waste

The Gannan region is the largest navel orange planting area in the world and has the largest production in China. However, about 5 million tons of navel orange waste (NOW) produced annually. NOW has a great environmental risk because of its high content of organic matter and moisture. Anaerobic digestion of NOW with high nitrogen content waste is a promising alternative to treat these wastes. The effect of swine manure (SM), waste active sludge (WAS) as co-substrates and different mixing ratio were examined in three batch-scale studies. In the first investigation, co-digestion of NOW with SM resulted low methane yield and high concentration of VFAs. In the second investigation, NOW was co-digested with WAS, the methane yield was improved by 260% when the mixing ratio of NOW to WAS (VS/VS) was shifted from 1:2 to 2:1. In the third investigation, the co-digestion of NOW with SM and WAS was conducted. Co-digestion of three substrates has higher methane yield than that of previous two studies, with the exception of equal amounts of NOW with co-substrates (mixing ratio of NOW to SM to WAS was 2:1:1). The highest methane yield of all experiments was 0.20 m3 kg-1VS added while the mixing ratio of NOW to SM to WAS was 1:2:1. It seemed to obtain stable digestion performance, the mixing ratio of co-substates to NOW should not be lower than 1:1. WAS was a better co-substrate than SM, as WAS was capable to supply more organic nitrogen to create positive synergistic effects.

scholarly journals Lignin oxidation products in soil, dripwater and speleothems from four different sites in New Zealand

2020 ◽  
Author(s):  
Inken Heidke ◽  
Adam Hartland ◽  
Denis Scholz ◽  
Andrew Pearson ◽  
John Hellstrom ◽  
...  
Keyword(s):  
New Zealand ◽  
High Resolution Mass Spectrometry ◽  
Lignin Content ◽  
Oxidation Products ◽  
Vegetation Changes ◽  
Original Source ◽  
Cave System ◽  
Open Questions ◽  
Lignin Oxidation ◽  
Ultrahigh Performance Liquid Chromatography

Abstract. Lignin oxidation products (LOPs) are widely used as vegetation proxies in climate archives, such as sediment and peat cores. The total LOP concentration, Σ8, provides information on the abundance of vegetation, while the ratios C / V and S / V of the different LOP groups also provide information on the type of vegetation. Recently, LOP analysis has been successfully applied to speleothem archives. However, there are many open questions concerning the transport and microbial degradation of LOPs on their way from the soil into the cave system. These processes could potentially alter the original source-dependent LOP signals, in particular the C / V and S / V ratios, and thus complicate their interpretation in terms of past vegetation changes. We analyzed LOPs in leaf litter and different soil horizons as well as dripwater and flowstone samples from four different cave sites from different vegetation zones in New Zealand using ultrahigh performance liquid chromatography coupled to high resolution mass spectrometry. We test whether the original source-dependent LOP signal of the overlying vegetation is preserved and can be recovered from flowstone samples and investigate how the signal is altered by the transport from the soil to the cave. The LOP concentrations range from mg/g in the soil to ng/g in the flowstones. Our results demonstrate that, from the soil to the flowstone, the C / V and S / V ratios both increase, while the total lignin content, Σ8, strongly decreases. This shows that the LOP signal is strongly influenced by both transport and degradation processes. Nevertheless, the relative LOP signal from the overlying soil at the different cave sites is preserved in the flowstone. We emphasize that for the interpretation of C / V and S / V ratios in terms of past vegetation changes, it is important to compare only samples of the same type (e.g., speleothem, dripwater or soil) and to evaluate only relative variations.

scholarly journals Removal of Emerging Contaminants in Wastewater by Sonolysis, Photocatalysis and Ozonation

2018 ◽  
Vol 21 (2) ◽  
pp. 98-105 ◽  
Keyword(s):  
Rate Constants ◽  
Photocatalytic Oxidation ◽  
Advanced Oxidation Processes ◽  
Emerging Contaminants ◽  
Removal Rate ◽  
Experimental Conditions ◽  
Oxidation Processes ◽  
First Order ◽  
Performance Variation ◽  
Pseudo First Order

<p>Three different advanced oxidation processes (AOPs) were applied to investigate the removal of emerging contaminants (ECs) i.e. sulfamethoxazole (SMX), diclofenac (DCF) and carbamazepine (CBZ) in synthetically prepared solutions. The degradation of these substances was carried out by ozonation, sonolysis and photocatalytic oxidation, as well as by different combinations of these processes. The objectives of this work were to evaluate the removal efficiency in each AOP and to assess the performance variation of sonolysis in combination with other AOPs. The best performances were achieved by sonocatalysis, which resulted in the removal of the selected pharmaceuticals in the range between 37% and 47%. Under similar experimental conditions, the removal of the selected ECs by single compounds by ozonation was slightly lower than the removal of respective compounds in the mixture. Moreover, pseudo first-order removal rate constants of photocatalytic mineralization were determined as 9.33×10-2, 4.90×10-3, 1.06×10-2 min-1 for SMX, DCF and CBZ, respectively.</p>

scholarly journals UV-Vis Spectroelectrochemistry of Oleuropein, Tyrosol, and p-Coumaric Acid Individually and in an Equimolar Combination. Differences in LC-ESI-MS2 Profiles of Oxidation Products and Their Neuroprotective Properties

Biomolecules ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 802 ◽  
Author(s):  
Morgane Lambert de Malezieu ◽  
Solenn Ferron ◽  
Aurélie Sauvager ◽  
Patricia Courtel ◽  
Charles Ramassamy ◽  
...  
Keyword(s):  
Neuronal Death ◽  
Oxidation Products ◽  
Coumaric Acid ◽  
Low Concentrations ◽  
Relevant Role ◽  
Electron Transfer Properties ◽  
Transfer Properties ◽  
Oxidized Products

Major phenolic compounds from olive oil (ArOH-EVOO), oleuropein (Ole), tyrosol (Tyr), and p-coumaric acid (p-Cou), are known for their antioxidant and neuroprotective properties. We previously demonstrated that their combination could potentiate their antioxidant activity in vitro and in cellulo. To further our knowledge of their electron-transfer properties, Ole, Tyr, and p-Cou underwent a spectroelectrochemical study, performed either individually or in equimolar mixtures. Two mixtures (Mix and Mix-seq) were prepared in order to determine whether distinct molecules could arise from their simultaneous or sequential oxidation. The comparison of Liquid Chromatography–Electrospray Ionization–Tandem Mass Spectrometry (LC-ESI-MS2) profiles highlighted the presence of specific oxidized products found in the mixes. We hypothesized that they derived from the dimerization between Tyr and Ole or p-Cou, which have reacted either in their native or oxidized forms. Moreover, Ole regenerates when the Mix undergoes oxidation. Our study also showed significant neuroprotection by oxidized Ole and oxidized Mix against H2O2 toxicity on SK-N-SH cells, after 24 h of treatment with very low concentrations (1 and 5 nM). This suggests the putative relevant role of oxidized Ole products to protect or delay neuronal death.

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