A novel pH-Dependent sensor for recognition of strontium ions in water: A hierarchically structured mesoporous architectonics

This paper reports the synthesis of a hierarchically structured mesoporous architectonics silica as a pH-dependent sensor for the detection and adsorption of strontium ions (Sr²⁺) from radioactive strontium-contaminated water. Herein, we designed a colored sensor based on the cubical mesoporous architectonics silica monoliths that enabled the detection of extremely harmful radioactive strontium ions (Sr²⁺) from drinking water. The surface-coating process of hierarchically cubical silica monoliths by one-step decoration using benzenesulfonic acid, 3-[[8-(acetylamino)-2-hydroxy-1-naphthalenyl]azo]-5-chloro-2-hydroxy-sodium salt signaling probe enabled us to create a unique pH-dependent colorant sensor. In this design, the high loading capacity and trapping of the chromogenic probe could be achieved, leading to the formation of an organic-inorganic hybrid that formed from cubically-silica pores and a chromogenic probe dressing layer. In this sensing system, a remarkable change in color and absorbance intensity of the sensor for strontium ions was observed at a pH value of 10.3. The synthesized cubically porous architectonic silica sensor is tailored to enable accessibility for continuous and efficient pH-dependent-strontium ion sensing capability concerning reversibility, selectivity, and signal stability.