Efforts on membrane properties and enzymes by adding divalent cations and sodium carboxymethyl cellulose

•The addition of sodium carboxymethyl cellulose improved the properties of membrane.•The addition of Co2+ to alginate gel improved activity of the enzyme.•Co2+ can improve the mechanical strength of microcapsules.•Co2+ replaced the Ca2+ in the traditional alginate gel.

In this paper, the addition of sodium carboxymethyl cellulose (NACMC) and cobalt ions to alginate gel significantly improved the inner and outer surface properties of membranes and the activity of the enzymes. The results showed the optimization was sodium alginate (SA) and NACMC at ratio 1:1, and the concentration of CoCl2 at 0.05 mol/L. The combined SA-NACMC gel bead apparently had a more porous and higher mechanical strength than that of the SA gel bead by scanning electron microscopy (SEM). The microcapsule surface roughness was measured by atomic force microscopy (AFM), the roughness was 155 ± 15.82 mm. Otherwise, the Brunauer–Emmett–Teller (BET) analysis showed that with the addition of NACMC the surface area and most of pore size of the microcapsules was 76.471 m2/g, and distributed in 3–25 nm, respectively. In 28d, immobilized enzyme had a higher degradation rate, and the atrazine residue of the immobilized enzyme with 5% content was 21.79%.