Study on Grouted Body Deterioration Mechanism of Sand Layer in Seawater Environment

Water-rich sand is a common stratum in marine underground engineering. Grouting is the most common method for solving geological disasters in water-rich sand. However, the marine environment differs greatly from the land environment. The erosion and seepage of seawater ion cause significant deterioration of grouted body, which reduces the physical and mechanical properties of grouted body. The maintenance of grouted body performance is the guarantee of long-term safe operation of the tunnel in the marine environment. In order to solve the problem of long-life grouting design for sand layer in seawater environment, an accelerated test of grouted body erosion under seawater erosion environment is designed to study the mesomorphological characteristics of seawater erosion on grouted body erosion and to reveal the mechanism of seawater erosion and solids. The evolution law of grouting plus solid strength under different slurry water-cement ratios and different seawater erosion time conditions is analyzed. The results show that the grouting plus solid effective time for water-cement ratios of 0.8 : 1, 1 : 1, 1.4 : 1, and 2 : 1 is 75a, 60a, 30a, and 15a; the index of strength degradation ratio of seawater environment to grouting plus solids is proposed, and the quantitative relationship between seawater erosion time and grouting plus solids strength is established, which provides theoretical basis for sand layer grouting reinforcement in seawater environment. We hope to provide some reference for the design and construction of sand grouting in seawater environment.

Efficient Catalytic Degradation of Phenol with Phthalocyanine-Immobilized Reduced Graphene–Bacterial Cellulose Nanocomposite

In this report, phthalocyanine (Pc)/reduced graphene (rG)/bacterial cellulose (BC) ternary nanocomposite, Pc-rGBC, was developed through the immobilization of Pc onto a reduced graphene–bacterial cellulose (rGBC) nanohybrid after the reduction of biosynthesized graphene oxide-bacterial cellulose (GOBC) with N2H4. Field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FT-IR) were employed to monitor all of the functionalization processes. The Pc-rGBC nanocomposite was applied for the treatment of phenol wastewater. Thanks to the synergistic effect of BC and rG, Pc-rGBC had good adsorption capacity to phenol molecules, and the equilibrium adsorption data fitted well with the Freundlich model. When H2O2 was presented as an oxidant, phenol could rapidly be catalytically decomposed by the Pc-rGBC nanocomposite; the phenol degradation ratio was more than 90% within 90 min of catalytic oxidation, and the recycling experiment showed that the Pc-rGBC nanocomposite had excellent recycling performance in the consecutive treatment of phenol wastewater. The HPLC result showed that several organic acids, such as oxalic acid, maleic acid, fumaric acid, glutaric acid, and adipic acid, were formed during the reaction. The chemical oxygen demand (COD) result indicated that the formed organic acids could be further mineralized to CO2 and H2O, and the mineralization ratio was more than 80% when the catalytic reaction time was prolonged to 4 h. This work is of vital importance, in terms of both academic research and industrial practice, to the design of Pc-based functional materials and their application in environmental purification.

Bacillus megaterium Biodegradation Glyphosate

The Bacillus megaterium ability was evaluated in this paper to degrade the Glyphosate. organophosphorus pesticides, The bacteria re-cultured that isolated from other researches of Baghdad soils and morphological identification and biochemical tests besides by selectivity media. The (5 and 25) ppm showed the highest growth results were within two days to two months on mineral salt media. The highest glyphosate degradation ratio % were (70) % per 25 ppm/two months. Incubation period Increasing led to highest glyphosate degradation ratio% at (25) ppm led to conclusion that bacteria digestive the pesticides as carbon and nitrogen sources and will be well harvest it form contaminated areas.

Azotobacter spp. Bioremediation Chemosate

Bioremediation of pesticides is the best option available to date due to its eco-friendly, cost-effective and efficacious nature. The study aimed to evaluate the Azotobacter spp. bioremediation Chemosate in the different incubation period and concentrations (5, 10, 15, 20, 25 ppm). From local sites, different microbes were isolated and Azotobacter separated using selective methods for identification of characteristics. The best result for the growth of Azotobacter sp. was at 25 ppm/0.222-0.163, in 15 days; in addition, the great degradation rate % was 25 ppm / 54.16%, observed in 2 months, while the best degradation and residues of chemosate after its digestion through MSM and HPLC residues analyses were at 25 ppm, as seen in 1-2 months, respectively. The degradation ratio % reached 81-79 % for 1-2 months. This conclusion suggests that Azotobacter spp. degradation Chemosate principles applied via hydrolysis binds phosphorus bonds with oxygen and digests the pesticides to produce nitrogen and carbon as elements for its growth sequences, especially at 2 months/25ppm.

Fe3O4-NPs/Orange-Peel composite as magnetic heterogeneous Fenton-like catalyst towards high-efficiency degradation of methyl orange

Fe3O4-NPs/orange-peel (MOP) composite was prepared via one-step in-situ co-precipitation method as magnetic heterogeneous Fenton-like catalyst. The properties of MOP were characterized by SEM, TEM, BET, XRD, FT-IR, TGA and XPS technologies. Its Fenton-like catalytic responses towards removal of methyl orange (MO) were investigated, in which the effects of initial dye concentration, pH, temperature and H2O2 dosage were studied. The MO degradation ratio up to 98.0% was obtained within 20 min in optimized conditions. The catalyst also shows excellent catalytic stability exhibiting nearly 90% degradation ratio in 10th cycle within 20 min, whereas pure Fe3O4-NPs showing only 62.5% in this stage. Due to the stabilization of complexing orange peel hydroxyl to Fe oxide in the composite and its magnetic separation property, Fe3O4-NPs/orange-peel composite exhibits excellent Fenton-like catalytic performance which offers great prospects for low-cost and high-efficiency organic dye wastewater treatment.

A Three-Component Hybrid Templated by Asymmetric Viologen Exhibiting Visible-Light-Driven Photocatalytic Degradation on Dye Pollutant in Maritime Accident Seawater

The increasing dangerous chemical pollutants led by shipping accidents call for the new pollutant treatment strategy. In this work, a new three-component hybrid {[(BiI6)I13]·2I3·(H-BPA)4}n (1) can be used in dye degradation in seawater. The highly interesting feature of 1 lies in its unique 1-D Z-shape [(BiI6)I13]n6− infinite chain constructed from the I···I contacts between mono-nuclear (BiI6)3− anions and I133− polyiodide anions. Finally, the hydrogen bonds between [(BiI6)I13]n6− polyanions and H-BPA2+ cations contribute to the formation a quasi-3-D network. Specifically, 1 exhibits the wide absorption zone from ultraviolet to visible regions and high charge-separation efficiency, hinting its application in visible-light catalysis. As expected, 1 represents photocatalytic activity for the degradation of rhodamine B in seawater with degradation ratio of 90%, and the photocatalytic performance is stable. This work might provide new photocatalytic material for pollutant treatment in shipping accidents.

Preparation and photo fenton-like activities of CuO/nanocellulose composite

A combination between the nanostructured photocatalyst and cellulose-based materials promotes a new functionality of cellulose towards the development of new bio-hybrid materials for water treatment and renewable energy applications. In this study, nanocellulose (CNC) was synthesized from sugarcane bagasse (SCB) biomass via formic /peroxyformic acid process treatment and acid hydrolysis at an atmospheric pressure. The resulting CNC of sugarcane bagasse were characterized by crystallinity index, chemical structure and morphology. X-ray diffraction (XRD) analysis revealed that the crystallinity increased with successive treatments. Images generated by TEM showed that CNC was rod-like in morphology, average diameter and length of 10 nm and 410 nm, respectively. The obtained CNC was used as a biotemplate for the synthesis of copper oxide (CuO) nanostructures through in - situ solution casting method. The photo-Fenton catalytic activity was evaluated via the degradation of methylene blue under sunlight irradiation with H2O2 as a oxidizing agent. The methylene blue degradation ratio of CuO/ CNC composite could achieve 98% in 150 min. The addition of H2O2 enhanced photocatalytic activities of the CuO/CNC. H2O2 not only prevented the recombination of charge carriers by accepting the photogenerated electrons and holes effectively but also produced additional OH.

Enhanced Biodegradation of Anthracene by Multi-Substrate Progressive Domestication of a Mixed Microbial Consortium With Pseudomonas_Aeruginosa DM3

The degradation of polycyclic aromatic hydrocarbons has attracted much attention. Based on toluene-catechol-anthracene multi-substrate progressive domestication, a mixed microbial consortium with synergistic metabolic activity was screened from the activated sludge of coking wastewater. High-throughput sequencing showed that the consortium was dominated by Flavobacteriia at the class level, with the proportion increasing from 8.88% to 56.41% after domestication, and that Myroides and Brevundimonas dominated at the genus level, increasing from less than 1% to 55.53% and 12.28%, respectively. Under temperature conditions of 30 °C, a pH of 7, and an initial anthracene concentration of 40 mg L-1, the degradation ratio reached 85.7% just 16 days after inoculation. Degradation ratio of Anthracene (40 mg L-1) via the consortium plus an indigenous strain Pseudomonas_aeruginosa DM3 on the sixth day (83%) equated to that in the control group without DM3 on the 12th day. The first-order rate constant (k=0.240 and 0.159 d-1) was calculated for the anthracene degradation within 10 days, with a corresponding half-life by the consortium of 2.9 days with DM3 and 4.4 days without DM3. The metabolites 1-naphthol, dibutyl phthalate, and 1,2-benzene dicarboxylic acid, mono (2-ethylhexyl) ester were presented in the reaction, inferring the metabolic pathway of phthalic acid. Our work revealed that inoculating the mixed microbial consortium with indigenous Pseudomonas aeruginosa DM3 has the potential for removing polycyclic aromatic hydrocarbons.

Characterization of Ligninolytic Bacteria and Analysis of Alkali-Lignin Biodegradation Products

Ligninolytic bacteria degrading lignin were isolates and identified, and their biodegradation mechanism of alkaline-lignin was investigated. Four strains with lignin degradation capability were screened and identified from the soil, straw, and silage based on their decolorizing capacity of aniline blue and colony size on alkaline-lignin medium. The degradation ratio of Bacillus aryabhattai BY5, Acinetobacter johnsonii LN2, Acinetobacter lwoffii LN4, and Micrococcus yunnanensis CL32 have been assayed using alkaline-lignin as the unique carbon source. Further, the Lip (lignin peroxidase) and Mnp (manganese peroxidase) activities of strains were investigated. Lip activity of A. lwoffii LN4 was highest after 72 h of incubation and reached 7151.7 U · l–1. Mnp activity of M. yunnanensis CL32 was highest after 48 h and reached 12533 U · l–1. The analysis of alkaline-lignin degradation products by GC-MS revealed that the strains screened could utilize aromatic esters compounds such as dibutyl phthalate (DBP), and decomposite monocyclic aromatic compounds through the DBP aerobic metabolic pathway. The results indicate that B. aryabhattai BY5, A. johnsonii LN2, A. lwoffii LN4, and M. yunnanensis CL32 have high potential to degrade alkaline-lignin, and might utilize aromatic compounds by DBP aerobic metabolic pathway in the process of lignin degradation.

Enhanced photocatalytic performance of NaNbO3 nanorods by loading Al2O3 nanoparticles

Herein, we report the fabrication of UV-active NaNbO3/Al2O3 (30 wt.%) ferroelectric heterojunction photocatalyst with enhanced photoelectrochemical activity to Methylene Blue (MB). Pure NaNbO3 nanorods (NRs) were synthesized by a facile hydrothermal process and NaNbO3/Al2O3 composite was prepared by an ultrasonic vibration method. The heterostructures showed a remarkable increase in photocurrent density and the MB degradation ratio reached 88% in the initial 15 min and eventually reached 98.6% in 75 min. The high photocatalytic efficiency is attributed to the ferroelectric polarization of NaNbO3 with the forming of heterojunction electric fields assisted by Al2O3. These properties demonstrate that NaNbO3/Al2O3 ferroelectric heterojunction photocatalyst shows promising photoactivity and provides an effective method to improve the photocatalytic properties of other ferroelectrics.