Continuous treatment of diethyl hexyl and dibutyl phthalates by fixed-bed reactor: comparison of two esterase bionanocomposites

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGThe removal of Diethyl hexyl phthalate (DEHP) and Dibutyl phthalate (DBP) is of great importance due to their potential adverse effects on the environment and human health. In this study, two bionanocomposites prepared by immobilization of Bacillus subtilis esterase by crosslinking to halloysite and supported in chitosan and alginate beads were studied and proposed as a green approach. The esterase immobilization was confirmed by physical–chemical characterization. Bionanocomposite using chitosan showed the best degradation levels in batch tests attaining complete degradation of DBP and around 90% of DEHP. To determine the operational stability and efficiency of the system, two fixed bed reactors filled with both bionanocomposites were carried out operating in continuous mode. Chitosan based bionanocomposite showed the best performance being able to completely remove DBP and more than 85% of DEHP at the different flowrates. These results proved the potential of these synthesized bionanocomposites to effectively remove Phthalic Acid Esters.Xunta de Galicia | Ref. ED431C 2021-43Agencia Estatal de Investigación | Ref. PCI2022-13294

Immobilization of esterase from Bacillus subtilis on Halloysite nanotubes and applications on dibutyl phthalate degradation

Dibutyl phthalate (DBP) is one of the listed phthalic acid esters (PAEs) known as the priority toxicants which exhibit carcinogenic and teratogenic properties and is responsible for endocrine disruption. Therefore, its removal has become a matter to tackle with. In this work, the feasibility of DBP degradation by esterase and lipase enzymes obtained from various microorganisms and the immobilization of the most effective in a clayey material were investigated. Esterase from Bacillus subtilis exhibited the highest degradation efficiency reaching a complete degradation. Its immobilization onto halloysite nanotubes (HNTs) by adsorption method was studied by response surface methodology using a central composite design face-centered. The four selected factors that affect the HNT-enzyme composite generation were: pH, adsorption time, enzyme/HNT (E/H) ratio, and adsorption temperature, and the optimal conditions were determined (pH 7, time 360 min, E/H ratio 0.2, temperature 30ºC). Consequently, the activity did not significantly decrease by immobilization, and the adsorption efficiency and relative activity were determined to be 73.15% and 82.7%, respectively. Besides, the immobilization enhanced thermal and storage stability. As for enzyme reusability, after 7 continuous cycles, the composite maintained almost 75% of its initial activity. Both the free enzyme (1 mg/mL) and the composite degraded 100 mg/L DBP with 100% efficiency and several byproducts were detected. Moreover, the composite could be reused for 7 cycles keeping a remarkable catalytic activity. Overall, this study indicated that the HNT-enzyme composite may be used as an effective candidate for remediation of the environmental media contaminated with DBP and other PAEs.Agencia Estatal de Investigación | Ref. PCI2022-132941Xunta de Galicia | Ref. ED431C 2021-43Universidade de Vigo/CISU

Water recovery with combined membrane system in textile industry, treatment and management of concentrates by hybrid advanced oxidation/membrane filtration

In this study, in addition to textile wastewater treatment by UF/NFtight/TO membrane combination of which efficiency is known, management has been performed for membrane concentrates generated with advanced oxidation combined process (Fenton and photo-Fenton (UVA-365-UVC-254))/submerged UF system of membrane concentrates generated within 75-80% water recovery ratio by oxidizing them in optimum operating conditions which were determined before. Ultimately in the studies, the conclusion has been reached that concentrate flows, generated as a result of the treatment with UF/NFtight/TO membrane configuration, were the highest performance innovative process by decreasing the sequential operated photo-Fenton (UVC-254)/UH050 hybrid process in ratios of 9.88 H2O2/TOK and 7.27 H2O2/Fe2+, in the filtration flux of 44 L/m(2). h, COD value to 167 mg/L with 86% COD removal, and TOK value to 104 mg/L with 74.2% TOC removal, after the oxidation with Fenton, photo-Fenton (UVA-365) and (UVC-254)/submerged UF system processes. When hazardous characteristics, removal/recovery methods and reuse alternatives of the concentrate remained after the oxidation of membrane concentrates generated were evaluated, it has been seen that all other concentrates of textile industry wastewater, except the concentrate generated by the treatment with photo-Fenton (UVA-365), had characteristics of hazardousness When removal/recovery methods were evaluated in detail, the conclusion has been reached that these concentrates could be removed with alternative options such as regular storage, burning and canalizing to central wastewater treatment system as long as necessary arrangements (moisture content, dehydration, suitable flow and/or mixture ratios) are made

Boron Oxide Production Kinetics Using Boric Acid as Raw Material

Boron oxide with a content of 99.93 wt.% from the dehydration of boric acid was synthesized. Conversion of boric acid to boron oxide was completed within 3 days at low temperature range (T 130 degrees C) for the isothermal dehydration reaction in the temperature range of 80 and 350 degrees C. Apparent activation energies were 65 and 28 kJ.mol(-1) for low and high temperature ranges, respectively. Thermogravimetric analysis (TGA) results showed that the reactions were nearly completed at around 330 degrees C, and activation energy for the first temperature region was found to be two-thirds of the isothermal value and the same for the second temperature region. Isothermal data analysis revealed that the apparent reaction order value was around 1.0 at low temperature range and decreased to 0.55 with temperature within the high temperature range

Physical and chemical properties of cow cockle seeds (Vaccaria hispanica (Mill.) Rauschert) genetic resources of Turkey

The seeds of Vaccaria hispanica (Mill.) Rauschert plant which spreads naturally in all regions of Turkey, have potential use in food and pharmaceutical industries. However, this plant, which is not well known, is not yet cultivated and used industrially. For sustainable industrial production, it is important to cultivate the seeds to obtain standard characteristic components such as superior starch granules, triterpenic saponins and cyclopeptides. The main objective of this study is to determine the content of the target components of the seeds obtained after adaptation to cultivation conditions among Vaccaria hispanica genotypes grown in nature. For this purpose, Vaccaria hispanica genotypes were collected, cultivated and analyzed regarding certain physical and chemical properties of seeds. The starch yield, segetalin A and saponin content of Vaccaria hispanica seeds were found in the range of 23.67-49.59 g/100 g dry seed, 0.17-0.65 g/100 g dry seed and 0.15-1.14 g/100 g dry seed, respectively. The thousand-grain weight, bulk density, moisture content, protein content, total phenolic and total fat content, and fatty acid composition were also determined. The seeds of Vaccaria hispanica genotypes were classified according to the analyzed parameters. All physical and chemical characteristics of the seeds subjected to principal component analyses and hierarchical cluster analyses which revealed that the total similarity values of the samples were determined to be 45.58% F1 and F2, 27.68% F1 and 17.90% F2; the samples were collected into three main groups

Gut dysbiosis may be associated with hyperemesis gravidarum

Purpose:In this study, we aimed to determine the frequency of different intestinal microorganisms of patients with normal pregnancies and HG and to compare these frequencies between the two groups. Materials and methods:This case-control study was carried out in Baskent University Department of Obstetrics and Gynecology and included 20 patients; 10 of whom had normal pregnancies and 10 of whom had HG. A stool flora scan was routinely planned for all patients. Transient and continuous fecal bacteria and fungal flora were analyzed. All data were evaluated statistically and their relationships with clinical condition were discussed. Results:The study group consisted of 20 pregnant women with a mean age of 31.5 years. All patients were nonsmokers and free of chronic diseases and of any medications. Aerobic and anaerobic bacteria groups, fungal colonies, and parasites were examined and bowel pH values were measured separately for each patient. Bacterial and fungal species outside the reference ranges were recorded for each patient. There was a statistically significant increase inClostridiumspp. (p:.01) andCandidaspp. (p:.033) and a statistically significant decrease inBifidobacteriumspp.(p:.008) in patients with HG compared to women with normal pregnancies. There was a significant difference between the group with HG and the group with normal pregnancies in terms of flora dysbiosis (p:.001). Conclusion:Our results suggest that gut dysbiosis may be a factor in HG. The effect of the severity of gut dysbiosis on the disease may be the subject of future studies

An unexpected diagnosis during laryngeal intubation: osseous polypoid lesion of the tongue: osteoma or choristoma?

Soft tissue osteoma is a rare entity having a strong predilection for the head and neck region, mainly posterior region of the tongue. The so-called lingual osteoma is mostly manifested as an asymptomatic exophytic lesion. It can be diagnosed by physical or radiological examinations

Assessment of epicardial fat and carotid intima media thickness in gestational hypertension

AimGestational hypertension (GHT) is a common disorder of pregnancy characterized by new onset hypertension without the presence of detectable proteinuria after 20 weeks of gestation. Epicardial fat thickness (EFT) and carotid intima media thickness (CIMT) are suggested as new predictors of subclinical atherosclerosis. Although the relationship between these parameters and essential hypertension has been demonstrated, this association in patients with GHT is still unknown. We aimed to investigate CIMT and EFT in patients with GHT

Novel hybrid treatments of textile wastewater by membrane oxidation reactor: Performance investigations, optimizations and efficiency comparisons

Feasible reclamation of industrial wastewaters by consuming less resource and time requires researchers to develop advanced and sophisticated solutions to meet today's versatile needs. In this respect, novel technological applications of hybrid membrane oxidation reactor (MOR) comprising of the Fenton or photo-Fenton enhanced ultrafiltration (FEUF and pFEUF), was demonstrated for treating textile washing wastewater. Their comparative hybrid performances were explored based on response surface analyses of Taguchi experimental designs that were optimized for maximized responses at minimum oxidant and acid consumptions. From eleven specific variables, those affecting the hybrid treatment performances at significant levels were found as H2O2 amount, process time, membrane type, Fe2+ concentration and temperature. The pFEUF treatment showed better and faster organics removal efficiency than by FEUF, and the UF process was seen to be more affected from changing operational conditions in pFEUF. Organic pollutants were oxidized by 56.6 +/- 8.7% degradation and 31.5 +/- 3.2% mineralization, while UF allowed a synergistic contribution to the hybrid MOR performance by 38.1 +/- 4.7% and 17.3 +/- 3.1%, respectively. Compared to simultaneous MOR and external UF after Fenton, sequential MOR was found as the best solution by an efficiency of 84.5% COD, 70.5% TOC, and 155.6 L/m(2).h. The effluents could be readily produced with quality suitable for directly discharging to the sewage infrastructure system resulting in a complete treatment. This study proved that the developed MOR techniques are technologically favorable for the treatment of industrial organic wastewaters due to high treatment performances and less resource, time and land needs. It can be finally declared that they can be used as rather attractive solutions for not only wastewater reclamation but also water recovery by further handling of their effluents. (C) 2019 Elsevier B.V. All rights reserved