The invention belongs to the field of environmental science, and discloses an adsorption film for a
biofilm DGT device, a preparation method and applications thereof. The preparation method comprisesthe following steps: 1) preparing an
agarose aqueous solution, and heating and cooling the
agarose aqueous solution; 2) uniformly mixing the
agarose aqueous solution treated in the step 1) with a suspension containing sensing-state microorganisms to obtain a
mixed solution, and preparing a film; and 3) soaking the film in a
ferric nitrate solution for a period of time to prepare an agarose
hydrogel film containing sensing-state microorganisms and
ferric oxide, and rinsing and soaking the film in a
buffer solution, carrying out shaking for a period of time, and washing and storing the film. According to the method, the sensing-state microorganisms and the
ferric oxide are combined and integrated in the adsorption film, and compared with the mode that in the prior art, the ferric
oxide adsorption film serves as the adsorption film, and the sensing-state microorganisms are loaded in the
diffusion film, the provided method is more sensitive to
toxicity response and is more conducive to accurate monitoring of a low-concentration target As.