Application of Ozone Involving Advanced Oxidation Processes to Remove Some Pharmaceutical Compounds from Urban Wastewaters

Different UVA radiation and advanced oxidation systems, most of them involving ozone, have been applied to remove mixtures of three contaminants of pharmaceutical type: diclofenac (DCF), sulfamethoxazole (SMT) and caffeine (CFF), both in ultrapure and secondary treated wastewater. The influence of the water matrix has been studied in terms of individual compound concentration and TOC removal. Also, biodegradability of the treated wastewater before and after the advanced oxidation process, as BOD/COD ratio, the partial oxidation yield, the increment of average state of carbon oxidation and ozone consumption have been determined. For mgL^?1 to 100 μgL^?1 concentrations and regardless of the ozone process and water type, DCF and SMT are removed in less than 10 min mainly by direct reaction with ozone, especially in the case of DCF. CFF, on the contrary, is mainly removed through hydroxyl radicals. For lower concentration (≤100 μgL^?1), DCF still disappears by direct ozonation, CFF by hydroxyl radicals oxidation and SMT through both direct ozonation and hydroxyl radical oxidation. Once DCF and SMT have disappeared, TOC is removed by reacting with hydroxyl radicals, regardless of the water matrix. Photocatalytic ozonation allows the highest TOC degradation rate, partial oxidation yield, increment of average state of carbon oxidation and biodegradability together to the lowest ozone consumption per mg TOC eliminated.     

Phenolic adhesives based on eucalyptus pyrolytic oil: Effect of urea addition on synthesis and properties

The present work aimed to evaluate the effect of urea addition on the synthesis parameters and properties of phenolic adhesives produced with oil from the pyrolysis of eucalyptus wood. The adhesive formulations were synthesized according to an entirely randomized design involving two formaldehyde/demethylated oil (F/DO) molar ratios (1.4 and 1.7), three NaOH/DO molar ratios (0.9, 1.0 and 1.1) and five levels of urea (0, 5, 10, 15 and 20%), totalizing 30 formulations. The following parameters and properties were obtained: reaction time (min) and temperature (°C); solids content (%), gel time (s), viscosity (cP) and pH. Regression analysis was performed and quadratic models were adjusted for reaction conditions (time and temperature) and some adhesive properties. Synthesis reactions were more controllable in terms of reaction time in the following conditions: urea addition in levels from 5 to 15% with F/DO molar ratio of 1.7 and NaOH/DO molar ratio of 1.0.     

Preparing phenolic resins using pulping spent liquor

The method of using spent liquor (SL) obtained from the chemical pretreatment stage of wheat straw semi-chemical pulping to prepare spent liquor phenolic resins (SLPR) was investigated in the present work. In this work spent liquor was modified with phenol, and then the modified spent liquor was further synthesized with phenol and formaldehyde under appropriate conditions. Experimental data shows that the substitution mass fraction of spent liquor for phenol, the mole ratios of formaldehyde and sodium hydroxide to phenol, temperature and duration time of addition and condensation reaction all show significant influence on the properties of SLPR. SLPR and pure phenolic resins (PR) exhibited almost the same macromolecular structures characterized by FT-IR, and the main properties of the SLPR such as free formaldehyde content, gel time and bonding strength demonstrated superiority to that of PR.     

Subsolidus solution and electrical properties of Sr-substituted bismuth magnesium niobate pyrochlores

Here we investigated the structural and dielectric properties of (Bi_3.36Mg_0.64-xSr_x)(Mg_1.28Nb_2.72)O_13.76 (0≤ x≤0.5) subsolidus solution. Sr-substituted bismuth magnesium niobate (BMSN) pyrochlores were prepared by solid-state reaction at 1025 °C over 1–2 days. X-ray diffraction (XRD) analysis confirmed that the BMSN pyrochlores crystallise in cubic symmetry, space group Fd3m with lattice parameters in the range 10.5968 (4)-10.5671 (17) Å. The surface morphologies of these samples, as confirmed by Scanning Electron Microscopy (SEM), were composed of irregular shaped grains. Both Scherrer and Williamson-Hall methods revealed that the crystallite sizes were in the range 46–75 nm. No thermal event was discernible over the temperature range 30–1000 °C, thus confirming the thermal stability of these materials. On the other hand, Arrhenius conductivity plots showed the BMSN pyrochlores to be highly insulating with activation energies of ~1.20–1.49 eV. At ~30 °C and 1 MHz, BMSN pyrochlores exhibited moderate high bulk dielectric constants, ɛ’, 90–186 and low dielectric losses, tan δ in the order of 10⁻²–10⁻¹, respectively. Both the ɛ’ and tan δ values of the BMSN pyrochlores showed a nearly two-fold decrease with increasing Sr concentration. Negative temperature coefficient of capacitances, TCC, −408 to −713 ppm/°C were recorded over ~30–300 °C at 1 MHz.     

尿素改性热塑性酚醛树脂的合成及应用

先用尿素、甲醛合成二羟甲脲，然后在酸性介质下把二羟甲脲滴加在苯酚中反应合成尿素改性的热塑性酚醛树脂。研究了反应浑浊点和二羟甲脲的滴加速度，同时研究了二羟甲脲与苯酚的尿酚比与物料的出料温度、产品产率及树脂理化性能指标的关系。结果表明：（1）二羟甲脲滴加速度的合适范围是0．012－0．029mol/mol.min；（2）本树脂的出料温度为125℃以下；（3）产品收率，游离酚，软化点随尿比的增长而递增，凝胶速度变化不大。另介绍了这种树脂在酚醛模塑料中的应用。     

Degradation of a Victorian brown coal in sub-critical water

Conversion characteristics of a Victorian brown coal in sub-critical water were investigated. Pulverized brown coal was heated up to 623 K in flowing sub-critical water pressurized at 25 MPa. The total conversion of the coal into extract and non-condensable gas reached over 70 wt%-daf, which was appreciably higher than the maximum conversion (50 wt%-daf) with a sub-critical non-hydrogen donor solvent, 1-methylnaphthalene (MN). Laser-ionization-desorption mass spectrometry showed that the sub-critical water extract was richer in lower-molecular-mass compounds than the sub-critical MN one. Thus, degradation of the coal occurred more extensively in sub-critical water than in MN. Along with the conversion in sub-critical water, both the total contents of hydrogen and phenolic hydroxyls in the whole products remained nearly unchanged. This suggests comparable and simultaneous formation and decomposition of hydroxyls through hydrolysis of ethers/esters and dehydration condensation between hydroxyls/carboxyls, respectively. For detecting the hydroxyl formation, the coal was first heated at 623 K under an inert gas atmosphere until the formation of water and the other volatiles was completed. Then, the heat-treated coal (LY-H) was exposed to flowing sub-critical water. As expected, the net formation of phenolic hydroxyls from LY-H was detected as 0.8 mmol-OH/g-LY-H while that of hydrogen as 2.3 mmol-H/g-LY-H. Approximately a half of the hydrogen gain was explained as phenolic hydroxyls gain, suggesting the importance of hydrolysis of esters and ethers that formed carboxyls and alcoholic hydroxyls as well as phenolic hydroxyls.     

Metal Ion‐Catalyzed Hydrothermal Liquefaction of Calcium Lignosulfonate in Subcritical Water

Three metal ion catalysts, namely, Na⁺, K⁺, and Ca²⁺, were tested to improve liquefaction of calcium lignosulfonate, and their effects on product distribution were specifically investigated. Results showed that metal ion catalysts favored the production of hydrogen as well as of phenolic compounds. The total contents of phenolic compounds catalyzed by metal ions were generally higher than 75 %. The catalysis abilities of Na⁺ and K⁺ were better than that of Ca²⁺. The neutral‐alkaline condition was much more beneficial to calcium lignosulfonate liquefaction. Compared to the hydrochars with Na⁺ and K⁺ catalysts, the hydrochars with Ca²⁺ catalyst had higher carbon content and a higher heating value.     

Degradation of Phenolic Compounds in Aqueous Sucrose Solutions by Ozonation

The sugar industry is concerned with color formation due to the oxidation of phenolic compounds in the presence of carbohydrates. In this study, we investigated the ozonation of a mixture of five phenolic compounds in water and aqueous sucrose solution: p-coumaric (p-COU), caffeic (CAF), syringic (SYR), and chlorogenic (CHO) acids, as well as the flavonoid quercetin (QUE). The experiments were carried out in a 3-L glass reactor with magnetic stirring and a diffuser plate at the bottom to feed the ozone-oxygen gas mixture. Initial solution concentrations of 5 mg L?1 of each acid, 15 mg L?1 of quercetin, and 40 g L?1 of sucrose were used. The degradation of phenolic compounds followed apparent first-order kinetics, with rate constants and percent removals decreasing in the presence of sucrose. In water, average consumed ozone dosages of 10.4 and 18.7 mg L?1 were necessary for 50% and 90% removals, respectively, for CHO, CAF, and p-COU; for QUE they were slightly higher (13.9 and 20.5 mg L?1, respectively). At a consumed dosage of 20.8 mg O3 L?1, more than 99% removal was obtained for CHO, CAF, and p-COU, while 96.2% was achieved for SYR. In contrast, QUE revealed to be more recalcitrant during ozonation in the absence of sucrose, with only 70% removal at the highest consumed O3 dosage. The consumed ozone dosages for 50% and 90% removals were higher for CHO, CAF, and p-COU in aqueous sucrose solution, which may impact ozone consumption during real sugarcane juice treatment. Sucrose and t-butanol were the main influential parameters that significantly affected the total amount of phenolic compounds degraded.     

Electrical Properties of Pre-Alloyed Cu-P Containing Electrically Conductive Adhesive

In this study, a pre-alloyed Cu-P powder with a trace amount of P (0.002 at.%) was used as a metallic filler in a phenolic resin-based electrically conductive adhesive (ECA). The electrical property of the Cu-P-filled ECA was investigated for long-term stability and reliability by aging at high temperature exposure at 125°C and 85°C/85% RH for 1000 h, respectively. Results showed that the electrical resistivity of the Cu-P-filled ECA could be maintained consistently low after high temperature exposure at 125°C for 1000 h or aging at 85°C/85% RH for 1000 h, compared with the rapidly increased resistivity of Cu-filled ECA over time. A significantly low final resistivity at an order of magnitude of 10^?4 Ω·cm could be maintained in Cu-P-filled ECA even after aging at 85°C/85% RH for 1000 h.