1,720,982 research outputs found
Synthesis, Characterization and Examination of Sorption Properties of Menengic-Based Biosorbents
No full textTekstil boyar maddeleri atık sularda bulunan, çevre ve insan sağlığını olumsuz yönde etkileyen kirleticilerdendir. Bu kimyasalların atık sulardan uzaklaştırılması canlı yaşamı için önemlidir. Menengiç iç kabuğundan oluşan toz haline getirilen malzemeyi kitosan ile kapladıktan sonra indigo karmin ve sülfür black olmak üzere iki tane boyar madde üzerinde çalışılmıştır. Bu çalışmada menengiç meyvesinin iç kabuğunun tozu kitosan ile modifiye edilerek mikro kapsül haline getirildi ve sulardan indigo karmin ve sülfür black uzaklaştırılması için kullanıldı. Adsorpsiyon deneyleri sırasında madde miktarı, zaman, konsantrasyon ve sıcaklık parametrelerin etkileri incelendi. Adsorpsiyon prosesinin indigo karmin için 0,04 g madde miktarında dengeye ulaştığı görülmüştür. Adsorpsiyon prosesinin indigo karmin için 120 dakika dengeye ulaştığı gözlemlenmiştir. Aynı zamanda indigo karmin çözelti pH değeri 2, diğer deneylerde sabit tutulmuş ve değiştirilmemiştir. Adsorpsiyon prosesinin sülfür black için 0,04 g madde miktarında dengeye ulaştığı görülmüştür. Adsorpsiyon prosesinin sülfür black için 60 dakika dengeye ulaştığı gözlemlenmiştir. Aynı zamanda sülfür black çözelti pH değeri 2, diğer deneylerde sabit tutulmuş ve değiştirilmemiştir. Çalışmaların son aşamasında, adsorpsiyon dengesinin matematiksel olarak tanımlanmasında Langmuir ve Freundlich adsorpsiyon modelleri kullanıldı ve model sabitleri hesaplandı. Sonuç olarak deneysel verilerin hem indigo carmin çözeltisi hem de sülfür black çözeltisi için Langmuir izoterm modeline uyduğu görülmüştür. Ayrıca kinetik verilerin birinci derece ve ikinci derece kinetik modellere uyumu araştırıldı, her modele ait kinetik sabitler bulunmuştur. Buna göre her iki boyar madde olan indigo karmin ve sülfür black çözeltilerinin ikinci derece kinetik modele daha uygun olduğu sabitlerden görülmüştür. Son olarak her sistem için adsorpsiyon termodinamik sabitleri olan ∆H, ∆S, ∆G termodinamik eşitlikler kullanılarak belirlenmiştir.Textile dyes are one of the pollutants found in wastewater, which negatively affect human and environmental health. Removal of these chemicals from wastewater is important for that life of the living beings. After coating powdered material consisting of the inner shell of menengic with chitosan, two dyestuffs, indigo carmine and sulfur black, were studied. In this study, the powder of the inner peel of the menengic fruit was modified with chitosan and turned into microcapsules and used for the removal of indigo carmine and sulfur black from water. During the adsorption experiments, the effects of parameters such as substance amount, time, concentration and temperature were investigated. It was observed that the adsorption process reached equilibrium for indigo carmine at the amount of 0.04 g substance. It was observed that the adsorption process reached equilibrium for indigo carmine in 120 minute. At the same time, the pH value of indigo carmine solution was kept constant and unchanged in other experiments. It was observed that the adsorption process reached equilibrium at 0.04 g of substance for sulfur black. It was observed that the adsorption process reached equilibrium at 60 minute for sulfur black. At the same time, the pH value of the sulfur black solution was kept constant at 2 in other experiments and was not changed. In the last stage of the studies, Langmuir and Freundlich adsorption models were used to define the adsorption equilibrium mathematically and the model constants were calculated. As a result, it was seen that the experimental data conformed to the Langmuir isotherm model for both the indigo carmin solution and the sulfur black solution. In addition, kinetic constants of each model were found by investigating the compatibility of kinetic data with first-order and second-order kinetic models. Accordingly, it was seen from the constants that both indigo carmine solution and the sulfur black solution were more suitable for the second order kinetic model. Finally, the adsorption thermodynamic constants ∆H, ∆S, ∆G for each system were determined using thermodynamic equations
Sorption of Heavy Metals on Clay Minerals and Oxides: A Review
No full textSorption of heavy metals plays a vital role in controlling environmental pollution. Here, we reviewed the sorption of heavy metals such as Ni, Co, Cu, Zn, V, Pb, Hg, In, As, Cd, Cr, Ga, Cs, Mn, V, Eu, Mo, Th, TI and Cr on metal oxides and clay minerals. The mechanism of association between these ions and the host minerals, and the factors controlling their sorption are discussed in detail. Both chemical and empirical methods of describing sorption mechanism are discussed. The sorption processes depend on the pH, metal concentration, ionic strength, temperature, time, adsorbent dosage, type of ion, surface area, type of adsorbent modification and nature of adsorbent. The review confirmed that both metal oxides and clay have capability of sequestering heavy metals, however, combination of both metal oxides and modified clay have enhanced capability of removing heavy metals from aqueous solution. These inorganic adsorbents have the regeneration and recycling potentials and can be used to remediate and sequester economic metals for commercial purposes, however, this needs future investigation
Advanced Sorption Process Applications
No full textAt the beginning of the twenty-firstst century, separation processes presented a comprehensive application of the major operations performed by various industries, such as chemical, food, environmental, and biotechnology. Sorption, one of the preferred separation processes because of its effectiveness at different interfaces, has caught the attention of many scientists. This book is aimed at gaining a general knowledge of sorption and a number of extremely important applications, as well as recognizing its functions and paramount importance in chemical and biochemical plants, including environmental treatment. Moreover, progress in the phenomenon is highlighted in this book. To help provide instruction in the important sorption processes, we have chosen authors who have extensive industrial and academic experience in closing the gap between theory and practice. Crucial progress in the theoretical information section of sorption has been achieved, mainly through the development of new techniques that examine the usage of various sorbents, including nanomaterials for the removal of various pollutants. We have subdivided the book into several sections, one of which is focused on applications of the sorption process, which presents real results of the recent studies and gives a source of up-to-date literature. The relationship between the sorption process and isotherm and kinetics modeling is analyzed in another chapter. This book will be a reference book for those who are interested in sorption techniques from various industries
Place of risk assessment studies within quality management systems and the application in pharmaceutical industry
No full textKalite yönetim sistemleri içerisinde, önleyici sistem yaklaşımlarında, kalite ile ilgili hatalar ortaya çıkmadan önce gerekli önleyici tedbirleri tespit ederek bu tedbirlerin alınması ile olası hataların önlenmesine olanak sağlayan en önemli planlama çalışması "Kalite Risk Yönetimi" sistematiğidir. Bu çalışmada, pek çok kimyasal ile çalışma yapılması ve detaylı prosesler içermesi nedeniyle iş güvenliği, çevre güvenliği, ürün kalitesi ve hasta sağlığının sağlanması ile ilgili pek çok risk içermekte olan ilaç endüstrisi için risk değerlendirme çalışmaları yürütülerek sonuçları paylaşılmıştır. Çevre, iş sağlığı ve güvenliği ile ürün güvenliği kalite yönetim sistemleri olmak üzere 3 ayrı kalite yönetim sistemi için risk değerlendirme çalışmaları yürütülmüştür. Bu sistemler için risk değerlendirme çalışmaları, yarı-kantitatif risk değerlendirme metodolojileri kullanılarak gerçekleştirilmiştir. GMP İyi İmalat Uygulamaları için "Hata Türleri ve Etkileri Analizi (FMEA)", ISO 14001:2004 Çevre Yönetim Sistemi için "Kinney Metodu" ve OHSAS 18001:2007 İş Sağlığı ve Güvenliği Yönetim Sistemi için "Kinney Metodu" kullanılarak 3 ayrı üretim operasyonu için risk analizleri gerçekleştirilmiştir. Kullanılan her 3 metodololoji de alınan önlem öncesi ve önlem sonrası risk seviyelerinin kıyaslanmasına imkan sağlayan metodlar olup bu çalışmada hiçbir önlem alınmayan duruma ait risk seviyesi belirlenmiş; ardından gerekli önlemler tanımlanarak, gerekli önlemler alındıktan sonra risk seviyeleri tekrar değerlendirilmiştir. Risk analizi sonuçları değerlendirildiğinde; gerekli yasal şartların ve sisteme ait özel şartların sağlanması ve riski bertaraf etmek için gerekli görülen diğer önlemlerin de alınması ile, kritik/tolerans gösterilemez risklerin bile minör/olası/önemsiz riske indirgenebildiği; gerekli önlemler alındığı halde risk seviyesi değiştirilemeyen bir risk senaryosunun mevcut olmadığı, kontrol metotlarının yeterli olduğu görülmüştür.Within quality management systems, the most important planning study in preventive system approaches is "Quality Risk Management" systematic which enables to prevent from probable quality failures by detecting required precautions before the failure arise and taking the preventive precautions. In this study, risk assessment studies were performed for pharmaceutical industry which has a lot of risk about ensuring occupational safety, environmental safety and product quality and patient health due to working with plenty of chemicals and possessing detailed processes and results were shared. Risk assessment studies were performed for 3 different quality management systems namely environmental, occupational health and safety and product safety quality management systems. Risk assessment studies for these systems were implemented by using semi-quantitative risk assessment methodologies. Risk analysis were performed in 3 different production operations by using "Failure Mode and Effects Analysis (FMEA)" for GMP Good Manufacturing Practices, "Kinney Method" for ISO 14001:2004 Environmental Management System and "Kinney Method" for ISO 18001:2007 Occupational Health and Safety Management System. Each of 3 methodologies used are methods providing opportunity to compare risk levels before and after taking precautions. In this study, risk level was determined for the case that any precaution has not been taken; then, required precautions were defined and risk level was re-determined for the case that the required precautions have been taken. When risk analysis results were evaluated; it was observed that by fulfilling regulatory requirements and particular requirements of system and by taking other necessary precautions for eliminating risk, even critical/non tolerable risks can be reduced to minor/probable/unimportant risks and there is no risk scenario that risk level cannot be changed even though required precautions have been taken and control methods are sufficient
Alternative Composite Nanosorbents Based on Turkish Perlite for the Removal of Cr(VI) from Aqueous Solution
Get PDFNew nanocomposite sorbents were synthesized and used for Cr(VI) removal from aqueous solution by modifying Turkish perlite with alpha-MnO2 (PAM) and gamma-Fe2O3 (PGI) nanoparticles. Nanocomposite sorbents were characterized using scanning electron microscopy (SEM) and FTIR. The effects of several parameters such as contact time, amount of sorbent, pH, and concentration were investigated and it was found that the sorption capacity for Cr(VI) was found to be highly pH dependent. Also the experimental data were evaluated in terms of different isotherm models. The data of PGI were well fit to DR isotherm model whereas PAM data were well described with Temkin isotherm model. The sorption capacities were found to be 8.64 and 7.6 mg g(-1) for PGI and PAM, respectively. This confirms that these nanocomposites retain the constituent nanoparticle properties while being macroscopic particles suitable for chromium removal in water treatment
Sorption and sorption-microfiltration hybrid system application for the removal of chromium ions from aqueous solutions
No full textBu çalışmada, Cr(III) ve Cr(VI) iyonlarının sulu çözeltilerden uzaklaştırılmasında bazı reçineler (katyon ve anyon değiştirici) iyon değiştirme prosesinde denenmiş, deneylerde, ortamın pH'ı, tutunma zamanı, metal iyon konsantrasyonu, sorbent miktarı, sıcaklık gibi parametrelerin metal uzaklaştırılmasındaki etkileri incelenmiştir. Daha sonra, birinci basamakta metal tutucu olarak iyon değiştirici kullanılmış ve mikrofiltrasyon (MF) membran ile sorbentin tutulması sağlanmıştır. Böylece sulu çözeltideki metal konsantrasyonunu mimimuma indirmek amacıyla hibrit sorpsiyon-mikrofiltrasyon sistemi uygulanmıştır. Metal-sorpsiyon işlemlerinde denge sorpsiyon izoterm eğrileri Freundlich, Langmuir, D-R ve Scatchard sorpsiyon izotermleri kullanılarak çizilmiş ve bu izotermlerden sorpsiyon parametreleri (k, n, As, Kb, Xm, K, E, Qs ve Ks) hesaplanmıştır. Ayrıca, deneyler sonunda birinci ve ikinci derece kinetik denklemleri verilere uygulanarak prosesin kinetiği de incelenmiştir.In this study, some resins (cation and anion exchangers) were used in ion-exchange process fro the removal of Cr(III) and Cr(VI) from aqueous solutions. In the experiments, the effects of parameters such as pH of the medium, contact time, metal ion concentration, amount of resin and temperature were investigated. After that, ionexchanger was used to remove metal at the first stage and microfiltration (MF) membrane was used to remove sorbent. Thus, hybrid sorption-microfiltration system was applied in rder to minimize the metal concentration in the aqueous solution. During metal-sorption processes, equilibrium sorption isotherm curves were obtained by Freundlich, Langmuir, D-R and Scatchard sorption isotherms and sorption parameters (k, n, As, Kb, Xm, K, E, Qs and Ks)were calculated. Moreover, the kinetics of the process was investigated by applying pseudo-first order and second order kinetic equations to the data obtained as a result of experiments
ORGANO-MODİFİYE NANOKİLİN ALTERNATİF BİR ADSORBAN OLARAK ATIKSULARDAN Cr(VI) UZAKLAŞTIRILMASINDA KULLANIMI
Get PDFBu çalışmada, organo-modifiyeli nanokilin sulardan Cr(VI) iyonlarının giderimindeki performansı değerlendirilmiştir. Organokillerin değişik pH aralığında ağır metalleri giderebildiği bilindiğinden, hem apolar organik kirleticiler hem de ağır metaller içeren karışık atık su sistemlerinde de etkili olabilecekleri düşünülmüştür. Bu amaçla, oktadesilamonyum (I30E, Nanomer, Nanocor, USA) ile modifiye edilmiş organo-montmorillonit nanokilin Cr(VI) adsorpsiyonunda kullanımı ve kesikli sistemde incelenen prosese temas süresi, çözelti pH'sı, başlangıç metal konsantrasyonu ve adsorban miktarı gibi parametrelerin etkisi incelenmiştir. Cr(VI) iyon miktarının sulu çözeltilerdeki tayini UV-visible spektrofotometre ile gerçekleştirilmiştir. Cr(VI) iyonunun organokile adsorpsiyonunda pH 2'de maksimum kapasite gözlenirken, pHʼnın 2ʼden 6ʼya arttırılmasıyla kapasite azalmıştır. Adsorpsiyon izotermlerinden Langmuir ve Freundlich izotermleri deneysel verilerin uygunluğunu test etmek için kullanılmış olup Cr(VI) iyonlarının organokil kullanılarak giderilmesinde gerçekleşen adsorpsiyon reaksiyonlarının Langmuir izoterm modeline uygun olduğunu göstermiştir
Methods of engineering of biopolymers and biocomposites
No full textBoth biopolymers and biocomposites have come to the fore as alternative materials in many areas due to the disadvantages of industrial polymers such as being obtained from depleted sources and difficult to dispose. This focus might arise in response to the social concerns regarding global warming and environmental pollution, shifting the focus toward materials made from renewable, biodegradable, and recyclable resources. Since they are obtained from natural and sustainable sources and have similar properties of industrial ones, owing to their improved mechanical and thermal properties, they are predicted to have an important place in various industries in the coming years. This chapter attempts to increase the knowledge base of these materials, especially in terms of their properties and production methods to maximize the current state-of-the-art applications. © 2021 Elsevier Ltd All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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