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In the present study both undoped CdSe and Zn-doped CdSe nanoparticles (NPs) were synthesized by a hydrothermal method previously reported in literature, with slight modification. The synthesized NPs were characterized using XRD and SEM. The SEM picture of undoped CdSe NPs showed sphere-shaped particles with a mean diameter of about 85 nm. All zinc-doped CdSe particles had rod-like structures with an approximate diameter ranging from 46 to 130 nm and a length up to 700 nm, depending on the amount of zinc added during synthesis. The Zn-doped CdSe NPs can catalyze the photodegradation of methylene blue (MB) and moxifloxacin (MOX) under UV illumination. The photocatalytic degradation efficiency of the Zn-doped catalysts showed an enhanced activity that reached up to 93% of MB degradation. The effects of some parameters such as amount of Zn dopant, catalyst loading, pH, reaction time and reaction temperature on the activity of the photocatalysts were also studied using MB solution as a model pollutant. The degradation efficiency of Zn-doped CdSe NPs for MOX was about 81.6% under UV irradiation for 110 min. These results suggest that the Zn-doped CdSe NPs can photocatalyze the degradation of not only MB but also organic micropollutants like MOX under UV irradiation The Zn-doped NPs can also decompose MB in daylight irradiation with 77.3% efficiency in 90 min which is promising for future application of solar light driven photocatalytic degradation of organic pollutants.
Tsegaye Girma Asere; Gijs Du Laing. Zn-doped CdSe nanoparticles: Impact of synthesis conditions on photocatalytic activity. Environmental Technology & Innovation 2020, 20, 101126 .
AMA StyleTsegaye Girma Asere, Gijs Du Laing. Zn-doped CdSe nanoparticles: Impact of synthesis conditions on photocatalytic activity. Environmental Technology & Innovation. 2020; 20 ():101126.
Chicago/Turabian StyleTsegaye Girma Asere; Gijs Du Laing. 2020. "Zn-doped CdSe nanoparticles: Impact of synthesis conditions on photocatalytic activity." Environmental Technology & Innovation 20, no. : 101126.
Platinum (Pt) and palladium (Pd) have widespread applications, such as in catalysts, jewelry, fuel cells, and electronics because of their favorable physical and chemical properties. Recovery of Pt and Pd from secondary sources is of great concern due to the increased market demand and limitation of the natural reserves of these precious metals. The aim of this research is to achieve recovery of Pt and Pd ions from dilute aqueous solution using dialdehyde of carboxymethyl cellulose (DCMC) crosslinked chitosan (Ch-DCMC). The DCMC was prepared by periodate oxidation of carboxymethyl cellulose (CMC). Both the DCMC and Ch-DCMC were characterized before and after Pt or Pd adsorption using Fourier-transformed infrared (FTIR) spectroscopy, X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM). The effect of cross-linking ratios of chitosan and DCMC (1:1, 1:0.8, 1:0.5, 1:0.25 and 1:0.1) on the Pt and Pd recovery was studied. The optimal cross-linking ratio was found to be 1:0.25 (chitosan: DCMC) with maximum adsorption capacity of 80.8 mg/g Pt and 89.4 mg/g Pd. High selectivity for Pt and Pd compared to base metals was achieved.
Tsegaye Girma Asere; Stein Mincke; Karel Folens; Flore Vanden Bussche; Linsey Lapeire; Kim Verbeken; Pascal Van Der Voort; Dejene A. Tessema; Gijs Du Laing; Christian V. Stevens. Dialdehyde carboxymethyl cellulose cross-linked chitosan for the recovery of palladium and platinum from aqueous solution. Reactive and Functional Polymers 2019, 141, 145 -154.
AMA StyleTsegaye Girma Asere, Stein Mincke, Karel Folens, Flore Vanden Bussche, Linsey Lapeire, Kim Verbeken, Pascal Van Der Voort, Dejene A. Tessema, Gijs Du Laing, Christian V. Stevens. Dialdehyde carboxymethyl cellulose cross-linked chitosan for the recovery of palladium and platinum from aqueous solution. Reactive and Functional Polymers. 2019; 141 ():145-154.
Chicago/Turabian StyleTsegaye Girma Asere; Stein Mincke; Karel Folens; Flore Vanden Bussche; Linsey Lapeire; Kim Verbeken; Pascal Van Der Voort; Dejene A. Tessema; Gijs Du Laing; Christian V. Stevens. 2019. "Dialdehyde carboxymethyl cellulose cross-linked chitosan for the recovery of palladium and platinum from aqueous solution." Reactive and Functional Polymers 141, no. : 145-154.
Arsenic (As) is a ubiquitous element found in the atmosphere, soils and rocks, natural waters and organisms. It is one of the most toxic elements and has been classified as a human carcinogen (group I). Arsenic contamination in the groundwater has been observed in >70 countries, like Bangladesh, India, West Bengal, Myanmar, Pakistan, Vietnam, Nepal, Cambodia, United States and China. About 200 million people are being exposed to excessive As through consumption of contaminated drinking water. Therefore, developing affordable and efficient techniques to remove As from drinking water is critical to protect human health. The currently available technologies include coagulation–flocculation, adsorption, ion exchange, electrochemical conversion and membrane technologies. However, most of the aforementioned treatment techniques require high initial and maintenance costs, and skilled manpower on top of that. Nowadays, adsorption has been accepted as a suitable removal technology, particularly for developing regions, because of its simple operation, potential for regeneration, and little toxic sludge generation. Processes based on the use of natural, locally available adsorbents are considered to be more accessible for developing countries, have a lower investment cost and a lower environmental impact (CO2 emission). To increase their performance, these materials may be chemically modified. Hence, this review paper presents progress of adsorption technologies for remediation of As contaminated water using chemically modified natural materials.
Tsegaye Girma Asere; Christian V. Stevens; Gijs Du Laing. Use of (modified) natural adsorbents for arsenic remediation: A review. Science of The Total Environment 2019, 676, 706 -720.
AMA StyleTsegaye Girma Asere, Christian V. Stevens, Gijs Du Laing. Use of (modified) natural adsorbents for arsenic remediation: A review. Science of The Total Environment. 2019; 676 ():706-720.
Chicago/Turabian StyleTsegaye Girma Asere; Christian V. Stevens; Gijs Du Laing. 2019. "Use of (modified) natural adsorbents for arsenic remediation: A review." Science of The Total Environment 676, no. : 706-720.
Chitosan biosorbents for the recovery of palladium and platinum from aqueous waste streams.
Stein Mincke; Tsegaye Grima Asere; Ivar Verheye; Karel Folens; Flore Vanden Bussche; Linsey Lapeire; Kim Verbeken; Pascal Van Der Voort; Dejene A. Tessema; Fekadu Fufa; Gijs Du Laing; Christian V. Stevens. Functionalized chitosan adsorbents allow recovery of palladium and platinum from acidic aqueous solutions. Green Chemistry 2019, 21, 2295 -2306.
AMA StyleStein Mincke, Tsegaye Grima Asere, Ivar Verheye, Karel Folens, Flore Vanden Bussche, Linsey Lapeire, Kim Verbeken, Pascal Van Der Voort, Dejene A. Tessema, Fekadu Fufa, Gijs Du Laing, Christian V. Stevens. Functionalized chitosan adsorbents allow recovery of palladium and platinum from acidic aqueous solutions. Green Chemistry. 2019; 21 (9):2295-2306.
Chicago/Turabian StyleStein Mincke; Tsegaye Grima Asere; Ivar Verheye; Karel Folens; Flore Vanden Bussche; Linsey Lapeire; Kim Verbeken; Pascal Van Der Voort; Dejene A. Tessema; Fekadu Fufa; Gijs Du Laing; Christian V. Stevens. 2019. "Functionalized chitosan adsorbents allow recovery of palladium and platinum from acidic aqueous solutions." Green Chemistry 21, no. 9: 2295-2306.
In different regions across the globe, elevated arsenic contents in the groundwater constitute a major health problem. In this work, a biopolymer chitosan has been blended with volcanic rocks (red scoria and pumice) for arsenic (V) removal. The effect of three blending ratios of chitosan and volcanic rocks (1:2, 1:5 and 1:10) on arsenic removal has been studied. The optimal blending ratio was 1:5 (chitosan: volcanic rocks) with maximum adsorption capacity of 0.72 mg/g and 0.71 mg/g for chitosan: red scoria (Ch–Rs) and chitosan: pumice (Ch–Pu), respectively. The experimental adsorption data fitted well a Langmuir isotherm (R2 > 0.99) and followed pseudo-second-order kinetics. The high stability of the materials and their high arsenic (V) removal efficiency (~93%) in a wide pH range (4 to 10) are useful for real field applications. Moreover, the blends could be regenerated using 0.05 M NaOH and used for several cycles without losing their original arsenic removal efficiency. The results of the study demonstrate that chitosan-volcanic rock blends should be further explored as a potential sustainable solution for removal of arsenic (V) from water.
Tsegaye Girma Asere; Stein Mincke; Jeriffa De Clercq; Kim Verbeken; Dejene A. Tessema; Fekadu Fufa; Christian V. Stevens; Gijs Du Laing. Removal of Arsenic (V) from Aqueous Solutions Using Chitosan–Red Scoria and Chitosan–Pumice Blends. International Journal of Environmental Research and Public Health 2017, 14, 895 .
AMA StyleTsegaye Girma Asere, Stein Mincke, Jeriffa De Clercq, Kim Verbeken, Dejene A. Tessema, Fekadu Fufa, Christian V. Stevens, Gijs Du Laing. Removal of Arsenic (V) from Aqueous Solutions Using Chitosan–Red Scoria and Chitosan–Pumice Blends. International Journal of Environmental Research and Public Health. 2017; 14 (8):895.
Chicago/Turabian StyleTsegaye Girma Asere; Stein Mincke; Jeriffa De Clercq; Kim Verbeken; Dejene A. Tessema; Fekadu Fufa; Christian V. Stevens; Gijs Du Laing. 2017. "Removal of Arsenic (V) from Aqueous Solutions Using Chitosan–Red Scoria and Chitosan–Pumice Blends." International Journal of Environmental Research and Public Health 14, no. 8: 895.
Contamination of drinking water with arsenic causes severe health problems in various world regions. Arsenic exists predominantly as As(III) and As(V) depending on the prevailing redox conditions of the environment. Most of the techniques developed for treating As(V) are not very effective for As(III), which is more toxic and mobile than As(V). In this study, novel cerium-loaded pumice (Ce-Pu) and red scoria (Ce-Rs) adsorbents were developed to remove both As(III) and As(V) ions from water. The Ce-Pu and Ce-Rs adsorbents were characterized using ICP-OES, EDX, and SEM. The experimental equilibrium sorption data fitted well Freundlich and Dubinin-Radushkevich (D-R) isotherms. The adsorption was very fast and reached an equilibrium within 2 h. Both Ce-Rs and Ce-Pu showed high As(III) and As(V) removal efficiency in a wide pH range between 3 and 9, which is an important asset for practical applications. The Ce-Pu and Ce-Rs adsorbents can be recycled and used up to three adsorption cycles without significant loss of their original efficiency. Accordingly, Ce-Pu and Ce-Rs seem to be suitable for removal of arsenic from aqueous systems.
Tsegaye Girma Asere; Kim Verbeken; Dejene A. Tessema; Fekadu Fufa; Christian V. Stevens; Gijs Du Laing. Adsorption of As(III) versus As(V) from aqueous solutions by cerium-loaded volcanic rocks. Environmental Science and Pollution Research 2017, 24, 20446 -20458.
AMA StyleTsegaye Girma Asere, Kim Verbeken, Dejene A. Tessema, Fekadu Fufa, Christian V. Stevens, Gijs Du Laing. Adsorption of As(III) versus As(V) from aqueous solutions by cerium-loaded volcanic rocks. Environmental Science and Pollution Research. 2017; 24 (25):20446-20458.
Chicago/Turabian StyleTsegaye Girma Asere; Kim Verbeken; Dejene A. Tessema; Fekadu Fufa; Christian V. Stevens; Gijs Du Laing. 2017. "Adsorption of As(III) versus As(V) from aqueous solutions by cerium-loaded volcanic rocks." Environmental Science and Pollution Research 24, no. 25: 20446-20458.
Tsegaye Girma Asere; Jeriffa De Clercq; Kim Verbeken; Dejene A. Tessema; Fekadu Fufa; Christian V. Stevens; Gijs Du Laing. Uptake of arsenate by aluminum (hydr)oxide coated red scoria and pumice. Applied Geochemistry 2017, 78, 83 -95.
AMA StyleTsegaye Girma Asere, Jeriffa De Clercq, Kim Verbeken, Dejene A. Tessema, Fekadu Fufa, Christian V. Stevens, Gijs Du Laing. Uptake of arsenate by aluminum (hydr)oxide coated red scoria and pumice. Applied Geochemistry. 2017; 78 ():83-95.
Chicago/Turabian StyleTsegaye Girma Asere; Jeriffa De Clercq; Kim Verbeken; Dejene A. Tessema; Fekadu Fufa; Christian V. Stevens; Gijs Du Laing. 2017. "Uptake of arsenate by aluminum (hydr)oxide coated red scoria and pumice." Applied Geochemistry 78, no. : 83-95.