Facile synthesis of polyamidoamine dendrimer gel with multiple amine groups as a super adsorbent for highly efficient and selective removal of anionic dyes.

Preparation of excellent dye adsorbent that simultaneously displays convenient separation capability, high adsorption capacity, fast removal rate, superior adsorption selectivity, and favorable reusability remains a challenge. Herein, we present a simple and feasible one-step method to prepare amine-rich porous polyamidoamine (PAMAM) dendrimer gel adsorbent. The PAMAM gel could be readily separated from water by filtration. The adsorption properties of PAMAM gel was systematically examined by adsorption of anionic methyl orange (MO) and tartrazine (TTZ) dyes. The PAMAM gel exhibited superior adsorption selectivity and removal efficiency towards anionic MO and TTZ dyes. The adsorption process could be completed within around 15 min and presented fine correlation with Langmuir isotherm and pseudo-second-order kinetic models. The maximum adsorption capacity of PAMAM gel towards MO and TTZ was as high as 680.2 mg g-1 and 689.7 mg g-1, respectively. Additionally, the dye-adsorbed PAMAM gel could be readily desorbed in alkaline solution. Considering the simple synthetic process and outstanding adsorption performance of PAMAM gel, this paper provides an effective approach to prepare high-performance anionic dye adsorbents.