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Commercial sponges in heterogeneous catalysis: developing novel composites with cobalt and silver

Żółtowska Sonia, Modelska Martyna, Piasecki Adam, Jesionowski Teofil

Physicochemical Problems of Mineral Processing

2020

Vol. 56, iss. 6

89--100

The use of commercial sponges in materials science has gained much recent attention. Their unique properties, namely a fibrous, rigid skeleton, thermal stability and resistance to acid and basic hydrolysis, have been the primary motivation to use them in the development of new composites. In this work, a simple method of immobilization of cobalt and silver cations, followed by their reduction using sodium borohydride, was successfully applied for the first time to obtain functionalized spongin scaffolds. Three different materials, labeled Co_spongin, Ag_spongin and Co-Ag_spongin, were prepared. Their morphological and physicochemical properties were explored using various techniques (SEM+EDS, TG/DTA, FTIR). The focal point of the research was the application of the resulting materials in the reaction of 4-nitrophenol reduction with sodium borohydride in water. It was found that all of the composites possess superior activity in the reduction of 4-nitrophenol, achieving high rate constants of 0.31 min-1 for Ag_spongin, 0.52 min-1 for Co_spongin and 0.86 min-1 for Co-Ag_spongin. Reusability tests showed that all of the composites could be reused five times. Additional structural analysis after catalytic application showed no visible changes in the morphology of the catalysts. The results indicate that spongin can be considered as a facile, cost-effective, renewable and environmentally friendly three-dimensional support for use in heterogeneous catalysis.

Adsorpcyjne usuwanie 4-nitrofenolu z wody

Gwadera M., Marcinek A.

Inżynieria i Aparatura Chemiczna

2015

Nr 2

36--37

Przeprowadzono badania doświadczalne równowagi i kinetyki adsorpcji 4-nitrofenolu z roztworu wodnego na węglu aktywnym. Przedstawiono model matematyczny procesu oparty na przybliżonym równaniu kinetyki adsorpcji. Wyniki badań doświadczalnych i numerycznych wykorzystano do wyznaczenia współczynnika dyfuzji składnika w ziarnach węgla aktywnego. Otrzymano wartość Ds=0,167-10-12m2/s.

Experimental study of equilibrium and kinetics of 4-nitrophenol adsorption from aqueous solution on activated carbon was investigated. A mathematical model of the process based on the approximate kinetic equation of adsorption is presented. The results of experimental and numerical studies were used to determine the diffusion coefficient in active carbon grains. A value of Ds equal to 0,167-10-12m2/s was obtained.