Abstract Treatment of wastewater has become vital to prevent environmental pollution in recent years. Adsorption is an easily applicable, low-cost and efficient method and is the subject of this study. In this study, an adsorbent was synthesized to be used in heavy metal removal using chitosan and starch. The composite was characterized by Fourier transform infrared (FTIR) spectrophotometry, X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis. It was determined that the composite had an amorphous and compact structure. Adsorption experiments were carried out under the optimized parameters such as solution pH, concentration, adsorbent amount, equilibrium time, and temperature. It shows that during adsorption, with the increase in pH, the adsorption efficiency and adsorption capacity first increase and then a fluctuation occurs. The highest adsorption efficiency and Q value were reached at pH 3.46 as 78% and 0.038 mol/kg, respectively. Moreover, the adsorption capacity (Q) reached its highest value with a value of 0.067 mol/kg in the presence of 30 mg adsorbent. Equilibrium experiments were validated by the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. To investigate the adsorption mechanism, pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models were used. It was determined that the adsorption process followed the D-R isotherm (R 2 = 0.99) and PSO (R 2 = 0.99). Therefore, the existence of chemical adsorption can be mentioned. Thermodynamic parameters enthalpy (∆H), Gibbs free energy (∆G) and entropy change (∆S) were investigated. The adsorbate-adsorbent interactions were studied by density functional theory (DFT).
A multielement preconcentration procedure based Fe 3 O 4 magnetic nanoparticles coated with polythiophene(Fe 3 O 4 @PTh MNPs) as a solid phase was reported for Cu(II), Co(II), Cd(II), Ni(II) and Zn(II) ions. Following the preconcentration, the ions were determined by microsample injection system-flame atomic absorption spectrometer (MIS-FAAS). The effect of sample pH, type and volume of eluent, sample volume, extraction time, amount of adsorbent and interfering ions were optimized. The analytes were preconcentrated from 75 to 150 mL of sample solutions buffered to pH 7. The eluent was 1 mL of 1 mol L -1 HNO 3 solution. Under optimum conditions, the limits of detection for the analyte ions varied from 1 to 10 μg L -1 . The adsorption capacities of Fe 3 O 4 @PTh was in the range of 2.85 to 9.76 mg g -1 . The method was validated by analysis of the certified reference materials. The relative errors and standard deviations were lower than 5%. The developed procedure was applied to various water, soil and some vegetable samples.
Abstract High-performance chemical systems designed to eliminate pollution caused by dyestuffs are still among the focuses of interest of chemists. Non-toxic biological materials especially have begun to be widely used in this field. Fourier transform infrared spectrometry, SEM (scanning electron microscopy), EDS (energy-dispersive X-ray analysis), and TGA (thermogravimetric analysis) were performed. Adsorption was performed in batch-adsorption experiments. Optimization processes involved pH, amounts of the sorbent and Safranin O, adsorption kinetics, desorption, and reusability. To highlight the mechanism of the interaction between Safranin O and S. porticalis and to predict the power and nature interactions, density functional theory computations were performed. Optimization processes included pH, amounts of sorbent and Safranin O, adsorption kinetics, desorption, and reusability. Experimental results were re-evaluated using Langmuir and Freundlich isotherm models and the biosorption process followed Freundlich isotherm kinetics. The biosorption mechanism was understood by pseudo-first-order (PFO), intraparticle diffusion (IPD), and Elovich models. Adsorption was determined to follow PFO kinetics: physical, endothermic, and spontaneous. The highest recovery was obtained in NaOH. Density functional theory (DFT) finding calculations were also performed to prove the high adsorption capacity for Safranin O of the material used.
Fen ve sağlık alanlarına ilgi duyan ve bu konularda çalışan herkesin yolu mutlaka kimyaya düşer. Kimya sayesinde hayatı, çevremizde olup bitenleri, canlılardaki değişimleri atom altı boyuttan devasa yapılara kadar her şeyi daha iyi anlarız. Temel bilimlerin en temel yapı taşlarından biri olan kimya, doğrudan biyoloji, fizik ve matematik gibi bilimlerle de iç içedir. Günümüzde onlarca alt bilim dalına ayrılan kimya temel düzeyde bütün bilim dalları için gereklidir. Bu nedenle kimya; dünyanın her yerinde tıp, biyokimya, eczacılık gibi sağlık bilimlerinin pek çok alanında, çevre, gıda, jeoloji ve maden bilimleri ile pek çok mühendislik alanında ve doğrudan fen bilimlerinin birçok alanında temel ders olarak okutulur.
새로운 동적 분광 광도 측정법은 천연의 물 샘플에서 망간(II)의 측정을 위해 개발되었다. 그 방법은 620 nm에서 활성화제로서 nitrilotriacetic acid (NTA)를 사용하면서 $KIO_4$에 의한 갈로시아닌(Gallocyanin)의 산화와 함께 망간(II)의 촉매 효과에 기초했다. 최적조건은 갈로시아닌(Gallocyanin) $4.00{\times}1^{-5}\;M$, $KIO_4$$1.00{\times}10^{-4}\;M$, NTA $1.00{\times}10^{-4}\;M$, pH = 3.50인 0.1 M HAc/NaAc 완충용액, 5분의 반응시간 그리고 $30^{\circ}C$의 온도에서 얻어졌다. 최적조건 하에서 제안된 방법은 $0.1\;-\;4.0\;ng\;mL^{-1}$의 범위에서 망간(II)의 측정을 허용했고 $0.025\;ng\;mL^{-1}$이하의 검출한계를 가지고 있다. 표준 망간(II) 용액을 측정하는 것에서 회수율은 98.5 - 102% 범위에 있다. 그리고 상대표준편차(RSD)는 0.76 - 1.25%의 범위에 있다. 새롭게 개발된 동적 방법은 약간의 주위의 물과 만족할 만한 결과를 갖는 JAC-0031의 공인된 표준 기준 강물 샘플 둘 다에서 망간(II)의 측정에 성공적으로 응용되었다. 또한, 얼마 안 되는 양이온과 음이온은 망간(II)의 측정을 방해한다. 다른 촉매-동적 방법과 기기적 방법과 비교했을 때, 제안된 동적 방법은 상당히 좋은 선택성과 감도, 낮은 가격, 저렴함, 낮은 검출한계와 신속함을 보인다. 상대적으로 낮은 염분을 갖는 진짜 물 샘플과 병으로 된 마시는 물, 차갑고 뜨거운 용천수, 호수, 강물 샘플 같은 복잡한 모체들에 적용하는 것은 쉽고 성공적으로 적용될 수 있다. A new kinetic spectrophotometric method is developed for the measurement of Mn(II) in natural water samples. The method is based on the catalytic effect of Mn(II) with the oxidation of Gallocyanin by $KIO_4$ using nitrilotriacetic acid (NTA) as an activation reagent at 620 nm. The optimum conditions obtained are $4.00{\times}1^{-5}\;M$ Gallocyanin, $KIO_4$, $1.00{\times}10^{-4}\;M$ NTA, 0.1 M HAc/NaAc buffer of pH = 3.50, the reaction time of 5 min and the temperature of $30^{\circ}C$. Under the optimum conditions, the proposed method allows the measurement of Mn(II) in a range of $0.1\;-\;4.0\;ng\;mL^{-1}$ and with a detection limit of down to $0.025\;ng\;mL^{-1}$. The recovery efficiency in measuring the standard Mn(II) solution is in a range of 98.5 - 102%, and the RSD is in a range of 0.76 - 1.25%. The newly developed kinetic method has been successfully applied to the measurement of Mn(II) in both some environmental water samples and certified standard reference river water sample, JAC-0031 with satisfying results. Moreover, few cations and anions interfere with the measurement of Mn(II). Compared with the other catalytic-kinetic methods and instrumental methods, the proposed kinetic method shows fairly good selectivity and sensitivity, low cost, cheapness, low detection limit and rapidity. It can easily and successfully be applied to the real water samples with relatively low salt content and complex matrices such as bottled drinking water, cold and hot spring waters, lake water, river water samples.
