Remarkable photocatalytic efficiency, economic analysis and recycling processes of Sn-Zn quantum dots oxides for Reactive Yellow 145 dye removal and real industrial wastewater treatment

The ultrasonic-chemical synthesis of pure tin dioxide quantum dots (SnO 2 QDs) and zinc-doped tin dioxide quantum dots (SnO 2 QDs/Zn s ) were reported for photocatalytic abatement of Reactive Yellow 145 (RY145) dye and real textile wastewater treatment. Structural characterization confirmed the retention of the rutile SnO 2 phase with quantum-confined crystallite sizes ranging from 7.47 to 9.63 nm, and uniform Zn incorporation without forming segregated ZnO phases at low doping levels, as evidenced by XRD and EDX mapping. Optical analyses revealed tunable bandgap energies from 3.06 eV in undoped SnO 2 QDs to 3.51 eV in higher Zn-doped samples. The photocatalytic activity, assessed via degradation kinetics of RY145 under Xenon lamp irradiation, demonstrated a marked improvement for SnO 2 QDs/Zn1 (4% Zn) with a rate constant (k) of 9.92 × 10 -3 s -1 , exceeding the performance of undoped SnO 2 QDs1 (k = 6.93 × 10 -3 s -1 ) and surpassing SnO 2 QDs/Zn2 (6% Zn) by over 320%. Notably, the catalysts maintained over 87% activity after seven recycling cycles in real industrial wastewater, emphasizing operational stability. An economic evaluation revealed a 25.4% cost reduction for SnO 2 QDs/Zn1 relative to SnO 2 QDs/Zn2. This investigation underscores the critical role of nanoscale structural engineering and dopant optimization in advancing semiconductor photocatalysts for environmental applications and water treatment technologies. • An economic evaluation revealed a 25.4% cost reduction for SnO 2 QDs/Zn1 relative to SnO 2 QDs/Zn2. • Photodegradation rate of RY145 dye in presence of SnO 2 QDs/Zn1 reached to 322% higher than SnO 2 QDs/Zn2 • Recycling processes efficeny after 7 times of real industrial wastewater samples reached to 87%. • Stability of the prepared cataylsts proved by FTIR spectra before and after 7 recycling processes.