Integration of CdS particles into sodium alginate aerogel with enhanced photocatalytic performance

•CdS particles were integrated into sodium alginate network.•CdS particles were highly dispersed in the composite aerogel matrix.•The SA/CdS-2 showed the optimum photocatalytic activity towards Cr (VI) reduction.•The aerogels exhibited excellent recyclability and stability. In the present work, CdS nanoparticles were integrated into sodium alginate aerogel matrix through a facile method. The CdS particles were successfully incorporated into the network of sodium alginate and highly distributed. Moreover, the accessibility of pore structures of sodium alginate was well-preserved. The resulting hybrid aerogels demonstrated high photocatalytic ability towards Cr (VI) reduction. SA/CdS-2 (mass ratio SA: CdS = 1:2) exhibited the highest reduction efficiency of Cr (VI), which could reduce the concentration of Cr (VI) to 0 mg/L after 60 min illumination. A probably adsorption-photoreduction mechanism was proposed and discussed in detail. The aerogels had excellent reusability and recyclability, avoiding secondary pollution. This work holds a promise to design and fabrication of CdS particles into three-dimensional aerogel network.