A tojáshéj jellemzése és adszorpciós tulajdonságai reaktív festék példáján keresztül: Characterization and adsorption properties of eggshell through the example of reactive dye

Statistical models examining the dyes and pigments market predicts global production growth of 5.2% by 2025. This can lead to serious environmental problems due to the adverse effects of dyes on aquatic ecosystems. The removal of organic dyes is thus a key task. Developing the adsorption technology used in the traditional water treatment process and making it more economical and greener, moreover, increasing its efficiency can serve as a solution. In our research, we used eggshells in different forms as adsorbents, comparing dye removal with untreated, calcined, and immobilized eggshells. In this way, the structure and composition of the eggshell, the parameters of the optimal removal of reactive azo dye were examined. We outline possible binding mechanisms, these results are based on preliminary research, isotherm, kinetics, diffusion models, as well as optimization research, furthermore, large-scale, analytical measurements. The results clearly demonstrate that eggshell in all three forms is a potentially useful material for removing reactive dyes from wastewater. Kivonat Statisztikai modellezések, amelyek a festékek és pigmentek piacát vizsgálja 2025-re 5,2%-os globális termelési növekedést jelez előre. Ez súlyos környezeti problémákhoz vezethet a színezékek vizes ökoszisztémákra gyakorolt ​​kedvezőtlen hatása miatt. A szerves festékanyagok eltávolítása így kulcsfontosságú feladat. A hagyományos víztisztítási eljárásban is használt adszorpciós technológia fejlesztése, gazdaságosabbá és zöldebbé tétele, hatékonyságának növelése megoldásként szolgálhat. Kutatásunk során tojáshéjat használtunk fel különböző formában adszorbensként, összehasonlítva a kezeletlen, kalcinált és immobilizált tojáshéjjal való festékeltávolítást. Vizsgáltuk ily módon a tojáshéj szerkezetét, összetételét, reaktív, azo-színezék optimális eltávolításának. Felvázoltunk lehetséges megkötési mechanizmusokat, eredményeinket előzetes kutatásokra, izoterma, kinetika, diffúziós modellekre alapozva, illetve az optimalizálási kutatásokra, nagyműszeres, analitikai mérésekre. Az eredmények egyértelműen bizonyítják, hogy a tojáshéj mindhárom formában potenciálisan hasznos anyag a reaktív színezékek szennyvízből történő eltávolításához

Performance Comparison of Eichhornia crassipes and Salvinia natans on Azo-Dye (Eriochrome Black T) Phytoremediation

Organic pollutants, such as dyes, have a negative effect on the aqueous environment, therefore, their elimination from water bodies is a high priority. In this work, Eichhornia crassipes and Salvinia natans, both model plants with high phytoremediation efficiency, were exposed to various concentrations (Ci = 50–500 mg/L) of Eriochrome Black T (EBT). Their capacity to assimilate EBT was studied for 16 days of exposure, similar to natural conditions and by spectrophotometric monitoring of the dye concentration (EE. crassipes; 150 mg/L = 33%; ES. natans; 150 mg/L = 71.5%). The changes of the experimental parameters (pH—equalised by day 5, temperature, humidity, light intensity) were followed, and plant growth and biochemical responses to toxic stress effects (photosynthetic pigments, Energy-dispersive X-ray spectroscopy (EDX)—decreased effect of P, Mg, Ca, S and K, Scanning electron microscopy (SEM), defense enzyme) were examined. Furthermore, changes in oxidative- and photo-degradation of EBT in time and the solid-state properties (SEM, EDX, Fourier-transform infrared spectroscopy-FTIR) of the dye were investigated. Our results demonstrate that, despite the toxic stress, both species succeeded in reducing the dye-concentration of the water and S. natans proved to be more efficient in binding and removing organic dyes. With our findings, we proved that both plants alleviated the abiotic stress of dye contamination

Effectiveness and Characterization of Novel Mineral Clay in Cd2+ Adsorption Process: Linear and Non-Linear Isotherm Regression Analysis

The excellent adsorption properties of clay minerals make the optimization of heavy metal removal the subject of numerous research projects. In the present study, ASLAVITAL cosmetic clay (ACC) powder was applied for the removal of Cd2+ from water. The main deposit of ACC clay is the Pădurea Craiului Mountains in Romania. A wide range of morpho-structural approaches (SEM, EDX, FTIR, Raman, XRD) were used to characterize the morphology and elemental composition of the adsorbent. As expected for clay minerals, Al (Wt(%) = 11.4 ± 0.9) and Si (Wt(%) = 13.7 ± 1.4) are the main constituents of ACC. After adsorption, Wt(%) = 0.2 ± 0.01 Cd2+ was detected in the sample. As proved before, the initial metal concentration is the primary influencing factor; therefore, batch adsorption of 10–160 mg/L Cd2+ was investigated. After 190 min, an efficiency of 99% was reached, and the quantity in equilibrium increased from 1–8 mg/g. The best fit in linear form was obtained for the Langmuir II. model, where R2 = 0.954 (RL = 0.037–0.027). Based on linear isotherm models, physical bonds formed between ACC and Cd2+ during the favorable adsorption. For the non-linear fits, the Liu model proved to be the best R2 = 0.965, χ2 = 1.101. Pseudo-II-order kinetic model described the experimental data R2 = 0.988–0.999; qexp and qcalc were almost identical (the differences ranged 0.03–0.34)

Living and non-living Biomass as Biosorbents for Heavy Metal Removal from Wastewaters

This PhD dissertation investigates the general subject area of environmental pollution, examining the possibilities of heavy metal (Cd2+, Zn2+, Cu2+) binding by means of various biosorbents. The present study assesses the adsorption capacity of new types of biosorbents, exploring their potentials in industrial applications. We have studied Scenedesmus opoliensis green algae and cultivated commercial and brewery waste Saccharomyces cerevisiae yeast cells in living, non-living and immobilised form. A PhD dolgozat a környezetszennyezés általános témakörével foglalkozik, ezen belül a nehézfémek (Cd2+, Zn2+, Cu2+) megkötési lehetőségeit vizsgálja, különböző bioszorbensek alkalmazásával. A dolgozatban új típusú bioszorbensek adszorpciós képességét tanulmányoztam az alkalmazási lehetőségek figyelembevételével. Scenedesmus opoliensis zöld algát és Saccharomyces cerevisiae tenyésztett, kereskedelmi, valamint sörgyári-hulladék élesztősejteket tanulmányoztam élő, élettelen és immobilizált formában

Factors Affecting Synthetic Dye Adsorption; Desorption Studies: A Review of Results from the Last Five Years (2017–2021)

The primary, most obvious parameter indicating water quality is the color of the water. Not only can it be aesthetically disturbing, but it can also be an indicator of contamination. Clean, high-quality water is a valuable, essential asset. Of the available technologies for removing dyes, adsorption is the most used method due to its ease of use, cost-effectiveness, and high efficiency. The adsorption process is influenced by several parameters, which are the basis of all laboratories researching the optimum conditions. The main objective of this review is to provide up-to-date information on the most studied influencing factors. The effects of initial dye concentration, pH, adsorbent dosage, particle size and temperature are illustrated through examples from the last five years (2017–2021) of research. Moreover, general trends are drawn based on these findings. The removal time ranged from 5 min to 36 h (E = 100% was achieved within 5–60 min). In addition, nearly 80% efficiency can be achieved with just 0.05 g of adsorbent. It is important to reduce adsorbent particle size (with Φ decrease E = 8–99%). Among the dyes analyzed in this paper, Methylene Blue, Congo Red, Malachite Green, Crystal Violet were the most frequently studied. Our conclusions are based on previously published literature

Linear and Nonlinear Regression Analysis for the Adsorption of Remazol Dye by Romanian Brewery Waste By-Product, Saccharomyces cerevisiae

Earth’s water balance and economy are becoming increasingly fragile due to overpopulation, global warming, severe environmental pollution and both surface and groundwater pollution. Therefore, it is essential to find solutions to the problems of water scarcity and water pollution. In this research, an experiment was designed to optimize the technique for the adsorption of Remazol Red F3B (RR) dye by lyophilized brewery yeast waste from the fermentation process. Moreover, we proved that brewery yeast is a great adsorbent. Batch adsorption experiments were carried out for optimization of different initial parameters, such as initial dye concentration (5–1000 mg/L), amount of yeast (0.5–2.5 g), pH (3–11) and temperature (20 to 40 °C). Furthermore, the structure and elemental composition of the adsorbent were analyzed with SEM, EDS and FTIR before and after biosorption. The best fits for the mathematical isotherm models in the case of the linear form were the Langmuir I and Freundlich models (R2 = 0.923 and R2 = 0.921) and, for the nonlinear form, the Khan model (R2 = 0.9996) was the best fit. The pseudo-second-order kinetic model showed the best fit for both linear (plotting t/qt vs. t) and nonlinear forms, are the calculated qe values were similar to the experimental data

Application of immobilized waste brewery yeast cells for Cd2+ removal. Equilibrium and kinetics

In this investigation, the removal of Cd2+ by a brewery waste biomass in immobilized (Ca alginate beads) form was studied. The removal process was conducted at room temperature under batch conditions (magnetic stirring) using different initial cadmium concentrations. The equilibrium of biosorption was reached in 150 min for all employed initial concentrations. The maximum biosorption capacity was calculated to be 5.96 mg Cd2+ g-1 yeast for an initial Cd2+ concentration of 169 mg L-1. Langmuir and Freundlich adsorption isotherms were used to correlate the equilibrium adsorption data. Based on the correlation coefficients, it was concluded that the Langmuir isotherm is more suitable for describing the equilibrium data of cadmium biosorption. In addition, first and pseudo-second order kinetic models were applied to describe the biosorption process. The kinetic parameters for the pseudo-second order kinetics were determined