Removal of ciprofloxacin from aqueous solution using wheat bran as adsorbent

Current study describes sorption of antibiotic drug (ciprofloxacin) by using nontoxic and biocompatible carrier, i.e., wheat bran (WB). For sorption study, various parameters were optimized and Freundlich, Dubinin–Radushkevich, Langmuir, and Temkin isotherm models were applied to demonstrate the mechanism of sorption, while kinetics study for sorption was evaluated using diffusion models, pseudo-first-order kinetic (Langergren) and pseudo-second-order (Ho and McKay) kinetic models. In addition, thermodynamics study was also carried out. However, sorption of ciprofloxacin was pH depended and it showed 75% drug release in alkaline medium (at pH = 1.5) indicating the good release ability of WB for ciprofloxacin.     

β-carotene rejection mechanism from organic medium by using activated carbon produced from waste biomass apricot

The present paper deals with the study of adsorption of β-carotene in tetrahydrofuran solution on activated carbon. Activated carbon was prepared from apricot waste, which is a by-product of apricot processing by means of chemical activation with ZnCl₂. BET surface area of activated carbon was measured to be 1060 m² g^?1. The effect of adsorption time, percentage of activated carbon in β-carotene solution, and β-carotene concentration on adsorption efficiency was also determined. Results were analyzed by the Langmiur, Freundlich, Dubinin?Redushkevich (D-R), Temkin, Frumkin, Harkins?Jura, Halse, Henderson, and Henry isotherms with linearized correlation coefficient. The characteristic parameters for each isotherm have also been determined. The kinetics of β-carotene adsorption has been discussed by the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, and the modified Freundlich equation. Three error analysis methods of residual mean square error (RMSE), chi-square statistic (χ²), and the average percentage error (% APE) have been used.     

Fabrication of a novel polyhedral oligomeric silsesquioxanes/polyether‐block‐amide nano‐hybrid membrane for pervaporative separation of model fuel butanol

The present study reports the pervaporative separation capability of the pristine and polyhedral oligomeric silsesquioxanes (POSS) loaded hybrid polyether‐block ‐amide (PEBA) membranes for n ‐butanol recovery from the dilute n ‐butanol–water mixtures. It is the first study to produce POSS‐loaded PEBA membranes for n ‐butanol recovery. The morphology and crosslinking structure of the pristine and hybrid membrane were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The thermal stability and crystallization behaviors of the pristine and hybrid membranes were investigated using thermogravimetric analysis and differential scanning calorimetry methods. Swelling experiments were also done to determine the affinity of the membranes to the n ‐butanol–water mixture. The effect of increasing amount of POSS on pervaporation performance was investigated in terms of flux and the n ‐butanol separation factor at 40 °C and a given n ‐butanol. All the hybrid membranes exhibited high flux and n ‐butanol separation factor than that of the pristine PEBA membrane. The best n ‐butanol separation factor of 27.2 was obtained accompanied with 1.33 Kg m^?2 h^?1 of flux, when the POSS amount was 4 wt %. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45211.     

Classification of eight pomegranate juices based on antioxidant capacity measured by four methods

The antioxidant capacity of pomegranate juices (PJs) obtained from eight cultivars were determined by the scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) and β-carotene-linoleate model system. Total phenolic content (TPC) and total anthocyanin content (TAC) were also determined and found to vary between the range of 208.3–343.6 mg catechin equivalents and 8.1–36.9 mg cyanidine-3-glucoside equivalents per 100 ml of PJ, respectively. Cultivar Izmir 8 showed the highest scores for trolox equivalent antioxidant capacity (TEAC) as 418.3 ± 5.2 mg/100 ml of PJ, anti-lipid peroxidative activity (ALPA) as 93.5 ± 1.8% and efficient concentration (EC₅₀) as 29.8 ± 2.9 ml of PJ/g of DPPH. The hierarchy of PJs for antioxidant capacity with respect to their TEAC and ALPA values was I8 > I1499 > I10 > I1264 > I1479 > I26 > I23 > Zivzik. Interrelationships among the analyzed parameters and PJs obtained from eight cultivars were investigated by principal component analysis (PCA). Dimension of data set was reduced to two components by PCA accounting for the 93% of the total variance. Eight PJs were classified into three groups by cluster analysis (CA).     

Applicability of a TSA/ZrO2 catalytic membrane for the production of ethyl levulinate as raw material of gamma-valerolactone

The aim of this study is to synthesize of ethyl levulinate as raw material by the green catalytic membrane process for the produce of gamma-valerolactone by hydrogenation. Production of zirconium oxide supported tungstosilicic acid loaded hydroxyethyl cellulose catalytic membrane was done by solution casting method. Zirconium oxide supported tungstosilicic acid, which used as the catalyst, was prepared by the wet impregnation method in the laboratory. Catalyst and catalytic membrane were characterized by XRD and SEM. The reaction was carried out in the batch reactor by using catalytic membrane pieces as the catalyst. Optimum conditions were determined as the reaction temperature of 75 °C, molar feed ratio of 6:1, catalyst concentration of 2 wt.% and catalytic membrane amount of 4 wt.%. The conversion value of levulinic acid to ethyl levulinate was obtained as 86% under these conditions and catalytic membrane was used for five times without losing catalytic activity. As a result of the study, catalytic membrane was found as an efficient catalyst for the synthesis of ethyl levulinate.     

Analyzing the Quality of Place: Creative Clusters in Soho and Beyoğlu

This paper analyzes the spatial characteristics of some parts of cities where the creative types (i.e. companies and people) involved in creative production are densely located. It aims to identify those socio-spatial factors that attract and retain creatives. In particular, it focuses on the film industry-based inner-city creative clusters, i.e. Soho in London and Beyo?lu in ?stanbul. This exploratory, cross-national, multiple case study applies the qualitative research techniques of interviews, observations, cognitive and cluster mapping. The paper concludes with the Analysis Framework for the Quality of Place which reveals the integrity of physical, socio-cultural, perceptual and visual characteristics of place. In particular, it discusses the key performance criteria and the scale of place which provides an inspiring and productive environment such as walkability, spatial proximity, and the public realm.     

MC-LMAC: A multi-channel MAC protocol for wireless sensor networks

In traditional wireless sensor network (WSN) applications, energy efficiency may be considered to be the most important concern whereas utilizing bandwidth and maximizing throughput are of secondary importance. However, recent applications, such as structural health monitoring, require high amounts of data to be collected at a faster rate. We present a multi-channel MAC protocol, MC-LMAC, designed with the objective of maximizing the throughput of WSNs by coordinating transmissions over multiple frequency channels. MC-LMAC takes advantage of interference and contention-free parallel transmissions on different channels. It is based on scheduled access which eases the coordination of nodes, dynamically switching their interfaces between channels and makes the protocol operate effectively with no collisions during peak traffic. Time is slotted and each node is assigned the control over a time slot to transmit on a particular channel. We analyze the performance of MC-LMAC with extensive simulations in Glomosim. MC-LMAC exhibits significant bandwidth utilization and high throughput while ensuring an energy-efficient operation. Moreover, MC-LMAC outperforms the contention-based multi-channel MMSN protocol, a cluster-based channel assignment method, and the single-channel CSMA in terms of data delivery ratio and throughput for high data rate, moderate-size networks of 100 nodes at different densities.     

Voltammetric characterization of selective potassium ion transfer across micro-water/1,2-dichloroethane interface facilitated by a novel calix[4]arene derivative

In this study, transfer reactions of alkali and alkaline-earth metal ions across a micro-water/1,2-dichloroethane (1,2-DCE) interface facilitated by a novel calix[4]arene derivative, 5,11,17,23-tetra-tert-butyl-25,27-bis(2′amino-methylpyridine)-26,28-dihydroxy calix[4]arene (APHC4), were investigated by cyclic and differential pulse voltammetry techniques. Well-defined voltammetric behavior was obtained only for K⁺ ion among the used metal ions. The electrochemical data were used to determine the stoichiometry and the appropriate association constant of the occurring complex between K⁺ ion and APHC4. The obtained steady-state voltammograms indicated that the facilitated transfer process occurs with a TIC/TID mechanism according to 1:1 stoichiometry. The logarithm of the association constant () of K(APHC4)⁺ complex in the DCE phase was calculated to be 6.32. Also, the availability of the facilitated transfer for the design of an amperometric screening sensor for K⁺ ion was evaluated in the range of 50–500 μmol dm⁻³.     

Improvement of polyvinyl alcohol/casein blend film properties by adding cellulose nanocrystals

This study aims to prepare and examine the properties of poly(vinyl alcohol)/casein (PVA/CAS) based films reinforced with cellulose nanocrystals (NC), which can be presented as an alternative to petroleum-based polymer packaging materials. PVA/CAS and 0.5–1–3–5 wt% NC containing PVA/CAS biocomposite films were prepared by solution casting method. Afterward, the 1NC film, which exhibited the best mechanical properties, was crosslinked with various amounts of glyoxal. Structural, morphological (polarized optical microscope), mechanical (tensile), thermal (differential scanning calorimetry, thermogravimetric analysis), contact angle, and water vapor transmission rate (WVTR) properties of the samples were investigated. The 1NC film exhibited the highest tensile strength (TS) and elongation values in PVA/CAS/NC films, and its mechanical properties decreased due to agglomeration with increasing NC amount. As expected, crosslinking improved the TS. The thermal stability of the PVA/CAS film was generally improved with the addition of NC and crosslinking. The high WVTR value of the PVA/CAS film decreased with the addition of NC and the 1NC film presented the lowest value. Thanks to the complex structure formed as a result of crosslinking and the reduced free volume, the WVTR of the 1NC film has reduced. The results showed that PVA/CAS-based films with good mechanical properties and water vapor barrier are promising as packaging materials.     

Pervaporation of MTBE/methanol mixtures through PVA membranes

Sorption and pervaporation experiments were carried outwith PVA/PAA cross-linked membranes for the separation of azeotropic methyl tert-butyl ether and methanol mixtures. The influence of the PVA/PAA ratio and liquid mixture composition were investigated. With increasing PAA content in the membranes, solubilities and fluxes decreased and selectivities increased. Total sorption and fluxes increased with increasing concentration of McOH. Increasing the concentration of McOH resulted in decreasing selectivities. Because of polarity, McOH permeated selectively through the membranes. Sorption results showed the same tendency with pervaporation results.