The development of highly reusable, non-toxic catalyst for the effective removal of 4-nitrophenol (4-NP) from marine water is a key challenge due to its diverse effects on living organisms. Herein, in situ green fabricated pyridinic N anchored Ag2O/Au decorated porous silica (CG-Ag2O/Au-SiO2) using spent coffee grounds (CG) powder is introduced as a reusable catalyst to mitigate 4-NP, Methylene blue (MB), Rhodamine 6G (R6G) and their mixture in the spiked deionized, river and marine water samples. Exceptionally high structural activity and excellent reusability of catalyst up to 15 cycles have been demonstrated due to the accessibility of a large number of active sites from pyridinic N anchored Ag2O and Au particle surfaces. CG-Ag2O/Au-SiO2 with the lower Ag and Au contents of 0.59 and 0.11 wt% (ICP-MS) of active catalytic sites exhibit a superior activity parameter of 6000 s-1g-1 (4-NP), 6357 s-1g-1 (MB), and 2892 s-1g-1 (R6G) than chemically synthesized and reported, bare and hybrid structures. Furthermore, the CG-Ag2O/Au-SiO2 shows excellent stability in marine water with promising reusability performance (≈93% after 15 successive cycles). Density functional theory (DFT) studies reveals that the observed high catalytic efficiency originates from the pyridinic N presence on the Ag2O/Au structures. This study opens the pathway for the rational design of hybrid catalysts utilizing abundant waste to effectively remove toxic pollutants in fresh, river, and marine water environments.
What will audience learn from your presentation?
- Necessity for developing such outstanding catalysts with use of sustainable support and reducing/stabilizing agents such as biogenic silica, and coffee grounds extract to fabricate hybrid structures (as catalysts), where suspended contaminants can be removed and makes the process economical and sustainable.
- Use of mesoporous support such as biogenic silica facilitates in-depth filtration (where the suspended contaminants are smaller than the pore volume), where suspended contaminants are trapped within the porous structure at various depths.
- The influence of two widely deployed techniques, namely chemical and greener synthesis for the catalytic reduction of 4-nitrophenol (4-NP) and degradation of organic dyes (methylene blue and rhodamine 6G) in spiked deionized, river and marine water samples.
- The effect of pyridic N in the catalytic activity.