scholarly journals Optimization with Response Surface Methodology of biosorption conditions of Hg(II) ions from aqueous media by Polyporus Squamosus fungi as a new biosorbent

2017 ◽  
Vol 43 (2) ◽  
pp. 37-43 ◽  
Author(s):  
Yusuf Uzun ◽  
Tekin Şahan

Abstract Removal of mercury(II) (Hg(II)) from aqueous media by a new biosorbent was carried out. Natural Polyporus squamosus fungus, which according to the literature has not been used for the purpose of Hg(II) biosorption before, was utilized as a low-cost biosorbent, and the biosorption conditions were analyzed by response surface methodology (RSM). Medium parameters which were expected to affect the biosorption of Hg(II) were determined to be initial pH, initial Hg(II) concentration (Co), temperature (T (°C)), and contact time (min). All experiments were carried out in a batch system using 250 mL fl asks containing 100 mL solution with a magnetic stirrer. The Hg(II) concentrations remaining in fi ltration solutions after biosorption were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Based on the RSM results, the optimal conditions were found to be 5.30, 47.39 mg/L, 20°C and 254.9 min for pH, Co, T (°C), and contact time, respectively. Under these optimal conditions, the maximum biosorbed amount and the biosorption yield were calculated to be 3.54 mg/g and 35.37%, respectively. This result was confi rmed by experiments. This result shows that Polyporus squamosus has a specifi c affi nity for Hg ions. Under optimal conditions, by increasing the amount of Polyporus squamosus used, it can be concluded that all Hg ions will be removed

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4430
Author(s):  
Nor Hakimin Abdullah ◽  
Mazlan Mohamed ◽  
Norshahidatul Akmar Mohd Shohaimi ◽  
Azwan Mat Lazim ◽  
Ahmad Zamani Abdul Halim ◽  
...  

The presence of organic dyes from industrial wastewater can cause pollution and exacerbate environmental problems; therefore, in the present work, activated carbon was synthesized from locally available oil palm trunk (OPT) biomass as a low-cost adsorbent to remove synthetic dye from aqueous media. The physical properties of the synthesized oil palm trunk activated carbon (OPTAC) were analyzed by SEM, FTIR-ATR, and XRD. The concurrent effects of the process variables (adsorbent dosage (g), methylene blue (MB) concentration (mg/L), and contact time (h)) on the MB removal percentage from aqueous solution were studied using a three-factor three-level Box–Behnken design (BBD) of response surface methodology (RSM), followed by the optimization of MB adsorption using OPTAC as the adsorbent. Based on the results of the analysis of variance (ANOVA) for the three parameters considered, adsorbent dosage (X1) is the most crucial parameter, with an F-value of 1857.43, followed by MB concentration (X2) and contact time (X3) with the F-values of 95.60 and 29.48, respectively. Furthermore, the highest MB removal efficiency of 97.9% was achieved at the optimum X1, X2, and X3 of 1.5 g, 200 mg/L, and 2 h, respectively.


Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 31 ◽  
Author(s):  
Jorge González-Rodríguez ◽  
Lucía Fernández ◽  
Yanina B. Bava ◽  
David Buceta ◽  
Carlos Vázquez-Vázquez ◽  
...  

Emerging contaminants (ECs) represent a wide range of compounds, whose complete elimination from wastewaters by conventional methods is not always guaranteed, posing human and environmental risks. Advanced oxidation processes (AOPs), based on the generation of highly oxidizing species, lead to the degradation of these ECs. In this context, TiO2 and ZnO are the most widely used inorganic photocatalysts, mainly due to their low cost and wide availability. The addition of small amounts of nanoclusters may imply enhanced light absorption and an attenuation effect on the recombination rate of electron/hole pairs, resulting in improved photocatalytic activity. In this work, we propose the use of silver nanoclusters deposited on ZnO nanoparticles (ZnO–Ag), with a view to evaluating their catalytic activity under both ultraviolet A (UVA) and visible light, in order to reduce energetic requirements in prospective applications on a larger scale. The catalysts were produced and then characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and inductively coupled plasma-optical emission spectrometry (ICP-OES). As proof of concept of the capacity of photocatalysts doped with nanoclusters, experiments were carried out to remove the azo dye Orange II (OII). The results demonstrated the high photocatalytic efficiency achieved thanks to the incorporation of nanoclusters, especially evident in the experiments performed under white light.


2021 ◽  
Vol 12 (4) ◽  
pp. 4567-4583

Tunics corm saffron (TCS) is a low-cost adsorbent that removes methylene blue (MB) from an aqueous solution. The TCS was characterized using FTIR and SEM analysis. The influence of MB adsorption variables such as TCS dose (0.4–2.4 g L−1), contact time (0–120 min), MB dye concentration (100–500 mg L−1) was optimized Box–Behnken design (BBD) combined with response surface methodology (RSM) modeling. All three variables among the main parameters significantly affected the removal efficiency by applying the quadratic regression analysis. The results showed that the predicted values for MB adsorption were close to the experimental values and were in good agreement. Besides, the r2 value (r2=0.970) indicates that the regression can predict response for the adsorption process in the studied range. The optimum BBD-RSM for MB removal of 89.48 % was recorded at a TCS dose of 1.78 g L−1, contact time of 56 min, MB dye concentration of 176 mg L–1 at solution pH of 5.4 temperature 21 °C. Excellent regeneration of TCS to remove MB in sixth consecutive adsorption-desorption cycles. This work highlights that TCS offers tremendous potential as a low-cost for organic dyes removal from wastewaters.


2019 ◽  
Vol 25 ◽  
pp. 1-11 ◽  
Author(s):  
Abiodun Paul Olalekan ◽  
Bamidele Sunday Fakinle ◽  
Adewunmi Oluwasogo Dada ◽  
Oghenerobo Benjamin Akpor ◽  
Oluwasola Oribayo

In this study, the Pb(II) ions adsorption unto nanoscale zerovalent iron particles (nZVI) supported on rice husk has been carried out. The challenge of nanoparticles agglomeration makes immobilising them on rice husk desirable. Optimization of process parameters, pH (4 – 10), adsorbent dose (0.5 – 2.0 g) and contact time (60 – 300 min), was carried out using response surface methodology (RSM) based on Box-Behnken design. Optimum condition for maximum Pb(II) ions of 98.74% was predicted at contact time of 60.12 min, pH of 4.01 and adsorbent dose of 0.5 g. At these optimized conditions, 97.23% removal was achieved experimentally. Analysis of variance carried out on the experimental data showed that the model was significant with a R2 of 0.9883. The synthesised adsorbent was characterized with Fourier transform-infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The SEM showed that RH-nZVI has a very porous surface structure. Amine, carboxyl and hydroxyl groups were some of the identified functional groups present in the adsorbent for adsorption. This study suggests that nZVI supported on rice husk is a viable low-cost adsorbent for removing Pb(II) ions from wastewater.


2019 ◽  
Vol 16 (3) ◽  
pp. 398-404 ◽  
Author(s):  
Yang Zou ◽  
Jingyi Fei ◽  
Liangzhe Chen ◽  
Qingfeng Dong ◽  
Houbin Li

Background: 3,3,7,7-tetrakis (difluoramino) octahydro-1,5-dinitro-1,5-diazocine (HNFX), as an important oxidizer in propellants, has received much attention due to its high density and energy. However, there are many difficulties that need to be solved, such as complex synthetic processes, low product yield, high cost of raw materials and complicated purification. In the synthesis of HNFX, the intermediate named 1,5-bis (p-toluenesulfonyl)-3,7-dihydroxyoctahydro-1, 5-diazocine (gem-diol), is difficult to synthesize. Methods: A simple method was used to synthesize the gem-diol. This prepared gem-diol was characterized by FT-IR, 1H NMR, melting point and mass spectrometry. In order to increase the yield of gem-diol, response surface methodology (RSM) was introduced to optimize experimental conditions. Results: After the establishment of the model, the optimal conditions of synthesis were found to be 9.33h for reaction time, 6.13wt. % for the concentration of NaOH and 1.38:1 for ratio of ECH (p-toluenesulfonamide): TCA (epichlorohydrin). Under the optimal conditions, the experimental value and the predicted value of yield were 22.18% and 22.92%, respectively. Conclusion: 1,5-bis (p-toluenesulfonyl)-3,7-dihydroxyoctahydro-1,5-diazocine (gem-diol) can be synthesized using the low cost of chemical materials, including p-toluenesulfonamide, epichlorohydrin, sodium hydroxide and ethanol. Response surface methodology (RSM) is an effective method to optimize the synthesis process, thereby improving the yield of gem-diol.


Beverages ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 4 ◽  
Author(s):  
Angela Soares ◽  
Nathalia M. Barros ◽  
Tatiana D Saint’Pierre ◽  
Juliana De P. Lima ◽  
Verônica Calado ◽  
...  

Micronutrient deficiencies are of great public health and socioeconomic importance. Food fortification has been widely used as a simple low-cost resource to increase mineral intake. Considering that coffee is the most consumed food product worldwide, in this study, C. arabica and C. canephora seeds were roasted, ground, and fortified with three salts of iron, zinc, and calcium as part of the selection of appropriate mineral vehicles for fortification. After ranking the performance through a test by a trained tasters’ panel, only two salts for each mineral remained. Mineral recoveries were evaluated by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) in filtered (paper and nylon filters) and espresso brews. The best mean recoveries for each mineral in espresso brew prepared from fortified coffees were: 80.8% of iron as ferrous bisglycinate chelate, 75.4% of zinc as zinc lactate, and 72.1% of calcium as calcium lactate. These better ranked salts by the tasters’ panel. In filtered brews, mean recovery values of 51.1%, 47.6%, and 51.6% were obtained for the same mineral salts, respectively. No difference or very small differences were observed between species and types of filter. The results implications are discussed.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mansoureh Daraie ◽  
Majid M. Heravi ◽  
Yalda Rangraz ◽  
Zahra Besharati

AbstractA hybrid system was designed and synthesized through reacting modified halloysite (Hal-Cl) with Schiff base (DAB-PC) and applied as catalytic support for anchoring Pd NPs to afford Pd@Hal-DAB-PC catalyst. The resultant material was well identified by various analyses including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction patterns (XRD), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and inductively coupled plasma-optical emission spectrometry (ICP-OES) and revealed outstanding catalytic activity in the Sonogashira reaction in aqueous media. Also, This nanocatalyst was simply collected and recycled up to six runs with a slight drop in efficiency, indicating the durability of Pd@Hal-DAB-PC.


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