Photocatalytic degradation and mineralization of diazinon in aqueous solution using nano-TiO2(Degussa, P25): kinetic and statistical analysis

Abstract: In this study, photocatalytic degradation of diazinon was investigated using nano-TiO2, Degussa P25, as a photocatalyst and the effects of some operational parameters such as aeration, pH, photocatalyst concentration, and the irradiation time were also examined. Dispersive liquid-liquid microextraction technique was used to extract and pre-concentration of residual diazinon from the liquid samples and all experiments were carried out by gas chromatography. Amount of degradation and mineralization were determined by gas chromatograph with flame ionization detector (GC/FID) and COD measurements, respectively. The optimum condition for degradation of diazinon has been obtained in the pH 6, [nano-TiO2] = 0.2 g/L, and [time] = 120 min. In the optimal condition the removal efficiency of diazinon and COD were 99.64 and 65%, respectively. The results have shown that the nano-TiO2, aeration and time of reaction have a positive effect on photocatalytic degradation of diazinon and COD removal. Statistical analysis showed that the maximum removal of diazinon and COD were due to UV irradiation (71%, 41%), exposure time (16%, 39%), aeration (7%, 4%), and increased concentration of nano-TiO2 (0.4%, 2%), respectively; and the kinetics of photodegradation were found to follow a first-order kinetic model and the constant rate, at optimal condition, was 0.038 (min−1). © 2014 Balaban Desalination Publications. All rights reserved

Optimization of organics and nitrogen removal in intermittently aerated vertical flow constructed wetlands: Effects of aeration time and aeration rate

© 2016 Elsevier Ltd In this study, to optimize aeration for the enhancement of organics and nitrogen removal in intermittently aerated vertical flow constructed wetlands (VF CWs) for treating domestic wastewater, the experimental VF CWs were operated at different aeration time (1 h d−1, 2 h d−1, 4 h d−1, 6 h d−1, 8 h d−1 and 10 h d−1) and aeration rate (0.1 L min−1, 0.2 L min−1, 0.5 L min−1, 1.0 L min−1 and 2.0 L min−1) to investigate the effect of artificial aeration on the removal efficiency of organics and nitrogen. The results showed that the optimal aeration time and aeration rate were 4 h d−1 and 1.0 L min−1, which could create the appropriate aerobic and anoxic regions in CWs with the greater removal of COD (97.2%), NH4+-N (98.4%) and TN (90.6%) achieved simultaneously during the experiment. The results demonstrate that the optimized intermittent aeration is reliable option to enhance the treatment performance of organics and nitrogen at a lower operating cost

Effect of L-Alanine on the Optical Properties of Zinc (Tris) Thiourea Sulfate (ZTS) Single Crystal

The growth of L-Alanine doped Zinc (tris) Thiourea Sulfate single crystal from aqueous solution by low temperature solution growth has been reported in the present investigation. The 1, 2 and 3mole% L-Alanine was doped in saturated ZTS solution. The effect of L-Alanine on SHG property was studied by Kurtz and Perry powder SHG test. The higher enhancement in SHG efficiency was observed at 1mole% L-Alanine doped ZTS. Hence, the growth 1mole% L-Alanine doped ZTS was carried. The grown crystal was characterized by single crystal X-ray analysis, FT-IR, UV-visible spectroscopy and thermal study by TGA and DSC analysis

Problems of the rotating-torsion-balance limit on the photon mass

We discuss the problems (and the promise) of the ingenious method introduced by Lakes, and recently improved on by Luo, to detect a possible small photon mass $\mu$ by measuring the ambient magnetic vector potential from large scale magnetic fields. We also point out how an improved ``indirect'' limit can be obtained using modern measurements of astrophysical magnetic fields and plasmas and that a good ``direct'' limit exists using properties of the solar wind.Comment: 4 pages, revised title and content

Synthesis and DNA interaction of a Sm(III) complex of a Schiff base derived from vanillin and L-tryptophan

The interaction between the Sm(III) complex of an ionic Schiff base [HL]-, derived from vanillin and L-tryptophan, and herring sperm DNA at physiological pH (7.40) has been studied by UV-Vis absorption, fluorescence and viscosity methods. The binding ratios nSm(III) : nK[HL] = 1:1 and nSm(III)L: nDNA = 5:1 were confirmed by a mole ratio method. The calculated binding constants of [Sm(III)L]+ with DNA at 25 and 37 oC were 1.19 × 105 M-1 and 3.96 × 104 M-1, respectively. The thermodynamic parameters demonstrate that the interaction between [Sm(III)L]+ and DNA is driven mainly by enthalpy. Fluorimetric studies show that [Sm(III)L]+ is able to displace intercalated acridine orange. Combined with Scatchard methods, circular dichroism spectroscopy and viscosity measurements, the results indicate that the interaction between [Sm(III)L]+ and herring sperm DNA is mainly by intercalation with some groove binding.KEY WORDS: Vanillin, L-Tryptophan, Sm(III) complex of Schiff base, Herring sperm DNA, Interaction Bull. Chem. Soc. Ethiop. 2011, 25(2), 197-207

An Empirical-Statistical Model for Landslide Runout Distance Prediction in Indonesia

There have been many attempts and methods for predicting landslide-affected areas; empirical methods, numerical methods, and laboratory models are commonly used for prediction. Laboratory and numerical models require an input of parameters that are difficult to determine accurately. At the same time, empirical statistical methods use statistical methods based on historical data of landslide events to form an empirical model. Statistical analysis of empirical observations builds a possible relationship between disaster area characteristics and slide behavior because it does not require detailed mechanics of avalanche movement; the empirical-statistical model is a simple and practical tool in the initial assessment to predict the sliding distance of an avalanche that will occur. The main discussion of this study is that the volume of avalanches (V) has a more significant influence than the height of the slope (H) on the length of the avalanche (L) that occurs. Fifty-nine data on landslide events that have occurred in Indonesia are used to a prediction model for landslide events reviewing the slope geometry parameters in the form of H, slope (θ), and V and discussing the main factors that affect the sliding distance of avalanches that have not been discussed in research in the Indonesian territory. The analysis shows that H has a significant effect on the sliding distance of the avalanche compared to V. The best model produced to predict the sliding distance of the avalanche is L = 6.918 H0,840 and produces an average error rate of 29% for the landslide measurement data

High mobility holes in a strained Ge quantum well grown on a thin and relaxed Si0.4Ge0.6/LT-Si0.4Ge0.6/Si(001) virtual

Epitaxial growth of a compressively strained Ge quantum well (QW) on an ultrathin, 345 nm thick, Si0.4Ge0.6/LT-Si0.4Ge0.6/Si(001) virtual substrate (VS) has been demonstrated. The VS, grown with a low temperature Si0.4Ge0.6 seed layer on a Si(001) substrate, is found to be fully relaxed and the Ge QW is fully strained. The temperature dependence of Hall mobility and carrier density clearly indicates a two-dimensional hole gas in the Ge QW. At room temperature, which is more relevant for electronic devices applications, the samples show a very high Hall mobility of 1235 cm2 V−1 s−1 at a carrier density of 2.36×1012 cm−2

Experimental study of an evanescent-field biosensor based on 1D photonic bandgap structures

[EN] A photonic bandgap (PBG) biosensor has been developed for the label-free detection of proteins. As the sensing in this type of structures is governed by the interaction between the evanescent field going into the cladding and the target analytes, scanning near-field optical microscopy has been used to characterize the profile of that evanescent field. The study confirms the strong exponential decrease of the signal as it goes into the cladding. This means that biorecognition events must occur as close to the PBG structure surface as possible in order to obtain the maximum sensing response. Within this context, the PBG biosensor has been biofunctionalized with half-antibodies specific to bovine serum albumin (BSA) using a UV-induced immobilization procedure. The use of half-antibodies allows one to reduce the thickness of the biorecognition volume down to ca. 2.5 nm, thus leading to a higher interaction with the evanescent field, as well as a proper orientation of their binding sites towards the target sample. Then, the biofunctionalized PBG biosensor has been used to perform a direct and real-time detection of the target BSA antigen.This research was funded by the European Commission through the Horizon 2020 Programme (PHC-634013-PHOCNOSIS project) and by the Spanish Ministry of Economy and Competitiveness (TEC2015-63838-C3-1-R-OPTONANOSENS project and FJCI-2015-27228 grant).Sabek, J.; Díaz-Fernández, FJ.; Torrijos-Morán, L.; Díaz-Betancor, Z.; Maquieira Catala, A.; Bañuls Polo, M.; Pinilla-Cienfuegos, E.... (2019). Experimental study of an evanescent-field biosensor based on 1D photonic bandgap structures. Beilstein Journal of Nanotechnology. 10:967-974. https://doi.org/10.3762/bjnano.10.97S96797410Wu, J., Dong, M., Santos, S., Rigatto, C., Liu, Y., & Lin, F. (2017). Lab-on-a-Chip Platforms for Detection of Cardiovascular Disease and Cancer Biomarkers. Sensors, 17(12), 2934. doi:10.3390/s17122934Qavi, A. J., Washburn, A. L., Byeon, J.-Y., & Bailey, R. C. (2009). Label-free technologies for quantitative multiparameter biological analysis. Analytical and Bioanalytical Chemistry, 394(1), 121-135. doi:10.1007/s00216-009-2637-8Luan, E., Shoman, H., Ratner, D., Cheung, K., & Chrostowski, L. (2018). Silicon Photonic Biosensors Using Label-Free Detection. Sensors, 18(10), 3519. doi:10.3390/s18103519Washburn, A. L., & Bailey, R. C. (2011). Photonics-on-a-chip: recent advances in integrated waveguides as enabling detection elements for real-world, lab-on-a-chip biosensing applications. The Analyst, 136(2), 227-236. doi:10.1039/c0an00449aIqbal, M., Gleeson, M. A., Spaugh, B., Tybor, F., Gunn, W. G., Hochberg, M., … Gunn, L. C. (2010). Label-Free Biosensor Arrays Based on Silicon Ring Resonators and High-Speed Optical Scanning Instrumentation. IEEE Journal of Selected Topics in Quantum Electronics, 16(3), 654-661. doi:10.1109/jstqe.2009.2032510Huertas, C. S., Fariña, D., & Lechuga, L. M. (2016). Direct and Label-Free Quantification of Micro-RNA-181a at Attomolar Level in Complex Media Using a Nanophotonic Biosensor. ACS Sensors, 1(6), 748-756. doi:10.1021/acssensors.6b00162Baker, J. E., Sriram, R., & Miller, B. L. (2015). Two-dimensional photonic crystals for sensitive microscale chemical and biochemical sensing. Lab on a Chip, 15(4), 971-990. doi:10.1039/c4lc01208aPhaner-Goutorbe, M., Dugas, V., Chevolot, Y., & Souteyrand, E. (2011). Silanization of silica and glass slides for DNA microarrays by impregnation and gas phase protocols: A comparative study. Materials Science and Engineering: C, 31(2), 384-390. doi:10.1016/j.msec.2010.10.016Díaz-Fernández, F. J., Pinilla-Cienfuegos, E., García-Meca, C., Lechago, S., Griol, A., & Martí, J. (2019). Characterisation of on-chip wireless interconnects based on silicon nanoantennas via near-field scanning optical microscopy. IET Optoelectronics, 13(2), 72-76. doi:10.1049/iet-opt.2018.507

REMOVAL OF EXCESS FLUORIDE FROM WATER BY ALUMINUM HYDROXIDE

The efficiency of untreated hydrated alumina (UHA) and thermally treated hydrated alumina (THA) obtained from hydrolysis of locally manufactured aluminum sulfate to remove fluoride from aqueous solution has been investigated in batch and continuous operation. The parameters considered were contact time and adsorbent dose, thermal pre-treatment of adsorbent, initial fluoride concentration and pH. The adsorption was rapid during the initial 20 min, but significant amount (> 90 %) was removed within one hour at an optimum adsorbent dose of 1.6 g/L for initial F- concentration of 20 mg/L. The removal efficiency of F was increased with adsorbent dosage. Fluoride adsorption efficiencies increase with increase in the thermal treatment temperature up to 200 °C, but further increase in temperature resulted in decreased removal efficiency. For application in continuous packed bed column, treatment at 300 °C was taken as an optimum value. Fluoride adsorption capacity increases linearly with increase in F- concentration. High defluoridation efficiency was achieved using both UHA and THA within a pH range of 4.0 to 9.0. The adsorption data at ambient pH were well fitted to the Freundlich isotherm model with a minimum capacity of 23.7 mg F-/g and 7.0 mg F-/g for THA and UHA, respectively. The kinetic studies showed that the adsorption reaction of fluoride removal by hydrated alumina can be well described by a pseudo-second-order rate equation. Continuous packed bed column experiment using THA indicated that 4.5 g of THA could treat 6 L of water containing 20 mg/L fluoride before breakthrough. Hence, both UHA and THA can be applied for the treatment of water with high fluoride content. KEY WORDS: Fluoride, Defluoridation, Hydrated alumina, Fluoride removal efficiency, Adsorption capacity, Adsorption kinetics, Breakthrough Bull. Chem. Soc. Ethiop. 2006, 20(1), 17-34

Effects of acute ammonia exposure and post-exposure recovery on nonspecific immunity in Clam Cyclina sinensis

This study aimed to assess the toxicity of ammonia on clam Cyclina sinensis and the post-exposure recovery. With increased exposure to TAN, the alkaline phosphatase (AKP) activities after exposure showed a trend of growing initially and subsequently decreasing, whereas the AKP activities after post-exposure recovery showed an increasing trend. The AKP activities after post-exposure recovery were significantly higher than those in control. The acid phosphatase (ACP) activities in T1 and T2 after post-exposure recovery were higher than those in the control, whereas the ACP activities in T3, T4, and T5 after post-exposure recovery were significantly higher than those in the control. The lysozyme (LZM) activities in T1 and T2 after exposure were significantly higher than those in control, whereas the LZM activities in T3, T4, and T5 after exposure were significantly lower than those in the control. Overall, ACP and LZM in the clams exposed to a low level of TAN (≤ 40 mg/L) can recover to the normal levels completely. However, a 48h recovery period scarcely seems adequate to compensate for AKP, ACP, and LZM activities in the clams exposed to a high level of TAN (> 40 mg/L)