An Assessment of Chromium (VI) Removal from Aqueous Solution Using Gelatin/PAAm-based IPN Hydrogels

In this work, gelatin (G)-polyacrylamide (PAAm)-based interpenetrating polymer network (IPN) hydrogels involving maleic acid (MA) was prepared using by radical polymerization. Full-IPN and semi-IPN hydrogels were synthesized by using glutaraldehyde and ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The water absorbency of hydrogels was investigated, and the values increased with MA and G. The chemical structures of full-IPN and semi-IPN hydrogels were tested by Fourier Transform Infrared Spectroscopy (FTIR). Morphological test was done by using Scanning Electron Microscope/ Energy Dispersive X-ray Spectroscopy (SEM/EDX). Thermal properties were examined with Differential scanning calorimeter (DSC) analyzer and Thermogravimetric analysis (TGA). The mechanical analysis was performed with Zwick Universal Testing Machine. Thermal and mechanical stabilities of full-IPN hydrogel was higher than semi-IPN. The efficiency of adsorption parameters (contact time, initial feed concentration, and pH) on Chromium (VI) ion adsorbing property of Full-IPN hydrogel was also determined. Isotherms were explained with the Langmuir or Freundlich equations. According to the results of both isotherms, it can be said that the hydrogel surface was homogeneous, and the adsorption of Chromium (VI) occurred in a monolayer

Development Of Sodıum Carboxymethyl Cellulose And Κ-Carrageenan Hydrogel Systems Contaınıng Varıous Mıcronutrıents And Investıgatıon Of Theır Effectıveness

Sunulan çalışmada, çeşitli mikro besin elementleri içeren sodyum karboksimetil selüloz (NaCMC) ve kappa-karragenan (κ-Karragenan) hidrojel sistemlerinin üretimi ve tarımsal amaçlı kullanılabilirlikleri araştırıldı. Çalışmanın birinci kısmında, FeCl3 iyonik çapraz bağlayıcısı kullanılarak ve polimer/çapraz bağlayıcı miktarları değiştirilerek 12 farklı NaCMC hidrojeli sentezlendi. Çalışmanın ikinci kısmında; farklı miktarlarda glutaraldehit (GA) içeren 6 farklı κ-Karragenan hidrojelleri kimyasal çapraz bağlanma yöntemiyle elde edildi. Üretilen NaCMC ve κ-Karragenan hidrojellerinin oluşum yüzdeleri belirlendikten sonra hidrojellerin şişme davranışları zamana, sıcaklığa ve pH'ya karşı incelendi. Hidrojellerin bozunma deneyleri 30ºC de ve pH=7,0 de yapıldı. Ayrıca hidrojellerinin FTIR ve SEM analizleri de gerçekleştirildi. NaCMC hidrojellerinin EDAX analizi, Fe3+ içeriğini saptayabilmek amacıyla yapıldı. SEM analizlerinden NaCMC hidrojellerinde tanecikliliğin ve gözenekliliğin çoğunlukla nano boyutta olduğu, κ-Karragenan hidrojellerinin gözenekliliğinin ise mikro boyutunda olduğu saptandı.Çalışmanın üçüncü kısmında; bakır, çinko ve mangan mikro besin elementleri, seçilen dört çeşit NaCMC ve üç çeşit κ-Karragenan hidrojellerine emdirme yöntemiyle yüklendi ve atomik absorpsiyon spektrometresi (AAS) ile in vitro, model ve toprak salım çalışmaları gerçekleştirildi. Çalışmanın son aşamasında; tarımsal uygulamaya örnek olmak amacıyla Zn2+, Cu2+ ve Mn2+ yüklü bir NaCMC ve bir κ-Karragenan hidrojellerinin buğday çim gelişimine etkisi araştırıldı. Genel olarak kullanılan mikro besin elementleri miktarı arttıkça, fide çıkış sayısı, fide boyu, gelişme ve uzama verimlerinin de önemli miktarda arttığı belirlendi. Sonuçlar Zn2+, Cu2+ ve Mn2+ etkisi açısından değerlendirildiğinde, en yüksek gelişme ve uzama veriminin Zn2+ içeren örneklerde elde edildiği saptandı.In this study, the production and the agricultural usability of sodium carboxymethyl cellulose (NaCMC) and kappa-carrageenan (κ-Carrageenan) hydrogel systems containing various micronutrients were investigated. In the first part of the study, 12 different NaCMC hydrogels were synthesized by using FeCl3 ionic crosslinker with changing polymer and crosslinker amounts. In the second part of the study, κ-Carrageenan hydrogels containing 6 different amounts of glutaraldehyde (GA) were synthesized with the chemical crosslinking method. The gel formation percentages of all produced hydrogels were determined then the swelling behaviors of hydrogels were investigated against time, temperature and pH. The degradation test of hydrogel was carried out at 30ºC pH=7.0 Moreover, hydrogels were analyzed with FTIR and SEM/EDAX. EDAX analysis of NaCMC hydrogels were performed in order to determine the contents of Fe3+. According to the SEM analysis, it was determined that granularity and porosity of the NaCMC hydrogel were mostly in the nanosize in case the porosity of the κ-Carrageenan hydrogels was in the micron size. In the third part of the study, copper, zinc, mangan micronutrients were loaded into four selected NaCMC and three selected κ-Carrageenan hydrogels by using soaking method and in vitro, model and soil release studies were carried out with Atomic Absorption Spectrometer (AAS). In the last part of study, the effects of Zn2+, Cu2+ ve Mn2+ loaded NaCMC and κ-Carrageenan hydrogels on wheatgrass growth were investigated to be an example for the agricultural application. It was determined that as the amount of micronutrients in general increased, the output seedling growth, growth and elongation efficiency increased significantly. When the results were analyzed with regards to the effect of Zn2+, Cu2+ and Mn2+, it was observed that the highest growth and elongation efficiency were obtained in samples containing Zn2+

Gelatin hydrogels synthesis, swelling/degradation behaviours investigation and formation of suitable immobilized lipase-gelatin hydrogels systems

Sunulan çalışmada lipaz immobilizasyonunda kullanılmak üzere bir seri jelatin hidrojel üretilmesi amaçlandı. Bu amaç doğrultusunda farklı oranlarda glutaraldehit (GA) çapraz bağlayıcısı içeren jelatin hidrojelleri hazırlandı ve bu hidrojellerin jelleşme yüzdeleri hesaplandı. Çapraz bağlayıcı miktarının artmasıyla jelleşme yüzdelerinin arttığı belirlendi. Hidrojellerin şişme davranışları zamana karşı incelendi. Tüm hidrojellerin şişme değerlerinin zamanla arttığı ve yaklaşık 48 saat sonra dengeye ulaştığı gözlendi. Artan çapraz bağlıyıcı miktarıyla şişme değerlerinin azaldığı belirlendi. 37ºC'de ve pH=7,4'de en çok şişen hidrojelin G-1 hidrojeli olduğu saptandı. Hidrojellerin şişme davranışlarının sıcaklıkla değişimi incelendi. Sıcaklık artışıyla şişme değerlerinin arttığı ve 40ºC'de en yüksek değerine ulaştığı gözlendi. Ayrıca hidrojellerin şişme davranışlarının pH ile değişimi de incelendi. Hidrojellerin düşük pH değerlerinde çok şiştiği, pH arttıkça şişme değerlerinin düştüğü ve pH=5,0'den sonra şişme değerlerinin yeniden yükseldiği gözlendi. Hidrojellerin bozunma davranışları 37ºC'de ve pH=7,4'de zamana karşı incelendi ve en düşük çapraz bağlayıcı içeren G-1 hidrojelinin 14 günde, diğer hidrojellerin ise yaklaşık olarak 30 günde tamamen bozunduğu gözlendi. Jelleşme ve şişme/bozunma testlerinin sonuçlarından yararlanılarak lipaz immobilizasyonuna uygun olarak G-2 hidrojeli seçildi. En verimli lipaz immobilizasyon koşullarını belirlemek amacıyla, seçilen G-2 hidrojeline karbodiimid (CDI) kullanılarak kovalent bağlanma yöntemi ile farklı derişimlerde lipaz immobilize edildi. İmmobilizasyonun gerçekleştiğini belirlemek amacıyla FTIR analizleri yapıldı. İmmobilize ve serbest lipazların aktivitelerine bakıldı ve serbest lipazın immobilize lipazlara göre daha aktif olduğu belirlendi. Daha sonra serbest ve immobilize lipazların kinetik parametreleri, Km ve Vmak değerleri, tayin edildi. Serbest ve immobilize lipazlar için Km değerleri sırasıyla 0,290 mM, 0,422 mM, Vmak değerleri sırasıyla 0,089 mM.dak-1, 0,080 mM.dak-1 olarak bulundu. Serbest ve immobilize lipazlar 4ºC'de 48 gün depolandıklarında, başlangıç aktifliklerinin sırasıyla %32 and %92'sini korudukları bulundu. Lipaz immobilize jelatin hidrojelinin 10 kez kullanımı sonucunda başlangıç aktifliğinin %68'ini koruduğu saptandı.In this study, it was aimed to produce a serial of gelatin hydrogel for utilizing in lipase immobilization. In order to do that gelatin hydrogels containing glutaraldehyde crosslinking in different values were prepared and the gelation percentages were calculated. It was found that with increase of the amount of crosslinking, gelation percentages increased as well. The swelling behaviour of hydrogels were investigated as a function of time. The percentage swelling of all the hydrogels were increased with time and after 48 hours constant percentage swelling were observed. It was determined that with increase of the amount of crosslinking, the swelling percentages increased as well. G-1 hydrogel was determined as the most swollen hydrogel at pH=7.4 and 37ºC. The swelling behaviours of hydrogels were also investigated by changing the temperature. The swelling values increased with temperature and maximum swelling percentage were observed at 40ºC for all the hydrogels. The swelling behaviours of hydrogels were also investigated by changing pH. It was observed that all the hydrogels were swollen more at low pH values but the percentage swelling values decreased with the increasing pH values and after at pH=5.0 it reincreased. The degradation behaviours of hydrogels were observed in terms of time at pH=7.4 and 37ºC. It was observed that G-1 hydrogel containing the least crosslinking degradated completely in 14 days, other hydrogels degradated completely in almost 30 days. By benefiting from the results of the gelation and swelling/degradation tests, G-2 hydrogel was chosen as in accordance with lipase immobilization. In order to determine the most efficiency lipase immobilization conditions, lipase was immobilized to the chosen G-2 hydrogel in different concentrations with the method of covalent bond by using carbodiimide (CDI). The FTIR analyzes were made for confirming the realization of the immobilization. The activities of immobilized and free lipases were examined and it was seen that free lipase was more active than immobilized lipases. After the kinetic parameters of the free and immobilized lipases, Km and Vmax, were assayed. Km and Vmax were calculated for free lipase as Km value is 0.290 mM, Vmax value is 0.089 mM.dak-1 and for immobilized lipase Km value is 0.422 mM, Vmax value is 0.080 mM.dak-1. After 48 days of storage at 4ºC, free and immobilized lipases retained %32 and %92 their orginal activities, respectively. Gelatin hydrogel immobilized lipase used repeatedly 10 times in a day and it was retained %68 their orginal activitiy

Gelatın hydrogels synthesıs, swellıng/degradatıon behavıours ınvestıgatıon and formatıon of suıtable immobilized lipase-gelatın hydrogels systems

Sunulan çalışmada lipaz immobilizasyonunda kullanılmak üzere bir seri jelatin hidrojel üretilmesi amaçlandı. Bu amaç doğrultusunda farklı oranlarda glutaraldehit (GA) çapraz bağlayıcısı içeren jelatin hidrojelleri hazırlandı ve bu hidrojellerin jelleşme yüzdeleri hesaplandı. Çapraz bağlayıcı miktarının artmasıyla jelleşme yüzdelerinin arttığı belirlendi.Hidrojellerin şişme davranışları zamana karşı incelendi. Tüm hidrojellerin şişme değerlerinin zamanla arttığı ve yaklaşık 48 saat sonra dengeye ulaştığı gözlendi. Artan çapraz bağlıyıcı miktarıyla şişme değerlerinin azaldığı belirlendi. 37ºC'de ve pH=7,4'de en çok şişen hidrojelin G-1 hidrojeli olduğu saptandı.Hidrojellerin şişme davranışlarının sıcaklıkla değişimi incelendi. Sıcaklık artışıyla şişme değerlerinin arttığı ve 40ºC'de en yüksek değerine ulaştığı gözlendi. Ayrıca hidrojellerin şişme davranışlarının pH ile değişimi de incelendi.Hidrojellerin düşük pH değerlerinde çok şiştiği, pH arttıkça şişme değerlerinin düştüğü ve pH=5,0'den sonra şişme değerlerinin yeniden yükseldiği gözlendi.Hidrojellerin bozunma davranışları 37ºC'de ve pH=7,4'de zamana karşı incelendi ve en düşük çapraz bağlayıcı içeren G-1 hidrojelinin 14 günde, diğer hidrojellerin ise yaklaşık olarak 30 günde tamamen bozunduğu gözlendi. Jelleşme ve şişme/bozunma testlerinin sonuçlarından yararlanılarak lipaz immobilizasyonuna uygun olarak G-2 hidrojeli seçildi. En verimli lipaz immobilizasyon koşullarını belirlemek amacıyla, seçilen G-2 hidrojeline karbodiimid (CDI) kullanılarak kovalent bağlanma yöntemi ile farklı derişimlerde lipaz immobilize edildi. İmmobilizasyonun gerçekleştiğini belirlemek amacıyla FTIR analizleri yapıldı. İmmobilize ve serbest lipazların aktivitelerine bakıldı ve serbest lipazın immobilize lipazlara göre daha aktif olduğu belirlendi. Daha sonra serbest ve immobilize lipazların kinetik parametreleri, Km ve Vmak değerleri, tayin edildi. Serbest ve immobilize lipazlar için Km değerleri sırasıyla 0,290 mM, 0,422 mM, Vmak değerleri sırasıyla 0,089 mM.dak-1, 0,080 mM.dak-1 olarak bulundu. Serbest ve immobilize lipazlar 4ºC'de 48 gün depolandıklarında, başlangıç aktifliklerinin sırasıyla %32 and %92'sini korudukları bulundu. Lipaz immobilize jelatin hidrojelinin 10 kez kullanımı sonucunda başlangıç aktifliğinin %68'ini koruduğu saptandı.In this study, it was aimed to produce a serial of gelatin hydrogel for utilizing in lipase immobilization. In order to do that gelatin hydrogels containing glutaraldehyde crosslinking in different values were prepared and the gelation percentages were calculated. It was found that with increase of the amount of crosslinking, gelation percentages increased as well. The swelling behaviour of hydrogels were investigated as a function of time. The percentage swelling of all the hydrogels were increased with time and after 48 hours constant percentage swelling were observed. It was determined that with increase of the amount of crosslinking, the swelling percentages increased as well. G-1 hydrogel was determined as the most swollen hydrogel at pH=7.4 and 37ºC. The swelling behaviours of hydrogels were also investigated by changing the temperature. The swelling values increased with temperature and maximum swelling percentage were observed at 40ºC for all the hydrogels. The swelling behaviours of hydrogels were also investigated by changing pH. It was observed that all the hydrogels were swollen more at low pH values but the percentage swelling values decreased with the increasing pH values and after at pH=5.0 it reincreased. The degradation behaviours of hydrogels were observed in terms of time at pH=7.4 and 37ºC. It was observed that G-1 hydrogel containing the least crosslinking degradated completely in 14 days, other hydrogels degradated completely in almost 30 days. By benefiting from the results of the gelation and swelling/degradation tests, G-2 hydrogel was chosen as in accordance with lipase immobilization. In order to determine the most efficiency lipase immobilization conditions, lipase was immobilized to the chosen G-2 hydrogel in different concentrations with the method of covalent bond by using carbodiimide (CDI). The FTIR analyzes were made for confirming the realization of the immobilization. The activities of immobilized and free lipases were examined and it was seen that free lipase was more active than immobilized lipases. After the kinetic parameters of the free and immobilized lipases, Km and Vmax, were assayed. Km and Vmax were calculated for free lipase as Km value is 0.290 mM, Vmax value is 0.089 mM.dak-1 and for immobilized lipase Km value is 0.422 mM, Vmax value is 0.080 mM.dak-1. After 48 days of storage at 4ºC, free and immobilized lipases retained %32 and %92 their orginal activities, respectively. Gelatin hydrogel immobilized lipase used repeatedly 10 times in a day and it was retained %68 their orginal activitiy

Interaction of copper (II) oxide nanoparticles with aquatic organisms: uptake, accumulation, and toxicity

Nanoparticles are used for several commercial applications, especially medical applications, energy-based research, and environmental applications. The usage of nanoparticles is increasing worldwide due to their unique properties, so all livings are exposed to these materials deliberately or unknowingly. The toxic nanoparticles disrupt the ecological balance of environment. The accumulation, surface area, particle size or shape of nanoparticles, exposure route, exposure time and dissolution contribute to the toxicity. The production of copper (II) oxide nanoparticles has expanded speedily in the last years so; it is important to know the risks that may be caused by their toxicological risks in ecosystems. This review emphasizes the environmental fate of copper (II) oxide nanoparticles. The environmental fate relates to their shapes, sizes, and physicochemical properties. The updated information on the toxicity of copper (II) oxide nanoparticles to aquatic organisms is given. Copper (II) oxide nanoparticles penetrate directly or indirectly into the organs of aquatic organisms through skin absorption, and/or nutrition. After the exposure, protein denaturation, protein oxidation, DNA damage, oxidative stress, generation of reactive oxygen species, hemolysis, and even cell death occurs in aquatic organisms. This review may assist in interdisciplinary studies to evaluate potential toxicity of copper (II) oxide nanoparticles in aquatic ecosystems

Alginate/carboxymethylcellulose-based hydrogels as pH-sensitive drug delivery systems: facile production with enhanced degradation, thermal and mechanical properties

pH-Sensitive alginate (ALG)/sodium carboxymethylcellulose (CMC) hydrogels were synthesized using a novel technique to utilize as a drug carrier in this study. The characterization of hydrogels was performed using FTIR (Fourier-transformed infrared spectroscopy), SEM(scanning electron microscopy), TGA (thermogravimetric analysis), DSC (differential scanning calorimetry), gel content and mechanical tests. The last technique is new and it is compared with the most well-known ionic crosslinking method to investigate the effectiveness of the technique. Gel content, degradation and thermal and mechanical stabilities were found to be higher. Swelling and degradation behaviors of hydrogels were studied in simulating gastric juice of pH 1.2 or simulating intestinal fluid of pH 6.8 and simulating colon fluid of pH 7.4 at 37 °C. The maximum swelling degree was observed at pH 7.4, and the minimum swelling degree was obtained at pH 1.2. An Anti-arrhythmics drug, propranolol hydrochloride (PPN), was loaded onto the obtained hydrogels as a model drug. Encapsulation efficiency (%) and drug loading amount (g/g) of ALG/CMC hydrogels synthesized by a new technique were found to be 61–68.4% and 0.152–0.171 g/g, respectively. The values of initial burst release at 15 min (%), drug released at 7 h (%) and equilibrium drug release were researched. Different kinetic model parameters (zero-order, first-order, Higuchi, and Korsmeyer–Peppas models) were calculated to investigate the drug release mechanism. The engineered hydrogels displayed controlled swelling capacity, cavitary surfaces, more porosity, high degradation resistance, gel content, thermal and mechanical properties and controlled drug release. These findings suggest that hydrogels synthesized by this new technique may be useful as a drug delivery system

Preparation and characterization of K-carrageenan hydrogel for controlled release of copper and manganese micronutrients

A series of ?-carrageenan (?-CG) hydrogels were prepared by using glutaraldehyde (GA) as crosslinker for controlled releasing of copper and manganese micronutrients. The hydrogels were characterized by gel content, swelling and degradation tests, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscope (SEM) observations. The variations of swelling percentages (S%) with time, temperature and pH were determined for all hydrogels. As the amounts of crosslinker increased, S% decreased regularly in contrast to gel content results. The higher swelling values were obtained in basic medium than acidic and neutral mediums for all ?-CG hydrogels. Releasing of copper and manganese micronutrients from ?-CG hydrogels was investigated in water and soil. A simulated releasing model was also applied to estimate the releasing behaviors in agricultural irrigations. In all release studies, the cumulative release values increased with decreasing GA amounts. The release kinetic parameters were also calculated. It was detected that the releasing of micronutrients in soil was slower than that in water. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

Effective Removal of Cationic Dyes from Aqueous Solutions by Using Black Cumin (Nigella sativa) Seed Pulp and Biochar

Black cumin seed pulp (C), as well as biochar (CC) produced via pyrolysis of black cumin seed pulp were used to remove methylene violet 2B (MV) and basic yellow 28 (BY28) from aqueous solution. Adsorption isotherms and kinetics were applied at 10, 25, and 35 °C. The adsorption of methylene violet 2B and basic yellow 28 on the black cumin seed pulp and biochar surface was exothermic; the heat of adsorption values were lower than 0. The adsorption capacities of BY28-C, BY28-CC, MV-C, and MV-CC were 212.8, 625, 164, and 909 mg g-1 at 25 °C, respectively. The adsorption of black cumin seed pulp and biochar data were examined with the Freundlich, Langmuir, Temkin, Dubinin-Radushkevich (D-R), and Flory-Huggins (F-H) isotherm models. The kinetics of the adsorption were fitted to the pseudo first-order and pseudo second order equations. The pseudo second order equation gave a better fit than the pseudo first-order equation

Controlled release behavior of zinc-loaded carboxymethyl cellulose and carrageenan hydrogels and their effects on wheatgrass growth

Akalın, Gülen Oytun ( Aksaray, Yazar )Sodium carboxymethyl cellulose (NaCMC) and carrageenan (CG) hydrogels were synthesized for potential use in the growth of wheatgrass plant. The water absorbency and gel content properties of prepared hydrogels were investigated. Water absorbency was reduced with increasing the amounts of polymer and crosslinker, in contrast with gel content results. The treatment of hydrogels with soil enhanced the water retention capacity of soil. Zinc micronutrient was loaded in both hydrogels by classic entrapment method. The zinc release behavior of hydrogels in water and soil were determined and the release rate decreased with high gel content and crosslinking density. The influence of zinc-loaded hydrogel on the wheatgrass plant performance were also investigated by using pot experiments. The growth of the wheatgrass (Triticum aestivum) was obviously increased by the use of zinc-loaded hydrogels. The increase in plant performance by using these hydrogels suggests that prepared hydrogels can be used as a controlled fertilizer system in agriculture fields

Preparation and characterization of nanoporous sodium carboxymethyl cellulose hydrogel beads

WOS: 000431221900001A series of nanoporous sodium carboxymethyl cellulose (NaCMC) hydrogel beads were prepared using FeCl3 ionic crosslinker by changing polymer and crosslinker percentages (%). Characteristics of the hydrogels were investigated by gel content, swelling test, degradation test, Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR), Scanning Electron Microscope/Energy Dispersive X-ray Analysis (SEM/EDX), and Atomic Force Microscopy (AFM). Swelling experiments were studied by changing time, temperature, and pH. The swelling percentage (S%) regularly decreased with increasing the amounts of polymer and crosslinker, in contrast with gel content results. NaCMC hydrogels were found to be sensitive to pH variations. The degradation test showed that hydrogels had good stability and their degradation period varied from 30 to 36 days. According to SEM analysis, NaCMC hydrogels had mostly nanoporous structure. The average granule and pore sizes of the least swollen NaCMC-12 hydrogel were found to be 13.1 +/- 0.3nm and 82.1 +/- 3.2 nm. The elemental compositions of hydrogels were determined with EDX. The minimum average surface roughness (R-a) and root mean square roughness (R-ms) parameters were found to be 15.7 +/- 1.9nm and 20.3 +/- 2.2nm for NaCMC-12 hydrogels by AFM. Due to their good morphologies, stabilities, and swelling behaviors, NaCMC hydrogels can be suitable for biomaterial applications.Scientific Research Projects Coordination Unit of Gazi University [05/2015-08]This work was financially supported by the Scientific Research Projects Coordination Unit of Gazi University (Grant no. 05/2015-08)