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Rising levels of antibiotics in treated wastewater pose a great threat to human health worldwide. The present study shows degradation studies of antibiotic Cephalexin using slurry and innovative fixed‐bed photocatalysis under UVA (365 nm) irradiations. A UV‐spectrophotometer/HPLC was used for analyzing the decay of Cephalexin. Studies showed that variation in UV intensity, dose variation of TiO2 and H2O2, area by volume (A/V), and pH affect the degradation to a great extent. The degradation rate followed pseudo‐first order kinetics with optimized conditions for degrading the antibiotic being TiO2 1.0 g · L−1, H2O2 0.15 mL, with UV intensity of 25 W · m−2. The COD decrease (80 %) with the generation of nitrite, nitrate, and sulphate ions confirmed the mineralization of the selected compound. TiO2‐coated spherical cement beads were used for fixed‐bed studies, which eliminates the implications of slurry mode photocatalysis. The beads were recycled for at least 50 cycles, which confirmed the durability of the catalyst, and characterized by SEM‐EDAX. Attempts were made to study the pilot‐scale fixed‐bed baffled solar reactor for degrading Cephalexin, which confirmed 70 % degradation after 10 h.

The fixed-bed photocatalytic degradation of fungicide carbendazim using catalyst-coated spherical cement beads has been investigated. Thirty beads with optimum size 13 mm along with 0.3 gL HO with an initial concentration of carbendazim of 10 mgL were the optimized conditions for better degradation. The reduction in COD and total organic carbon along with the generation of nitrite and nitrate ions under the optimized conditions confirms the complete mineralization of compound. The suggested degradation pathway for carbendazim has also been proposed as intermediates formed during photodegradation were analyzed through gas chromatography-mass spectrometry. The coated cement beads were found to be durable even after 30 cycles as confirmed by scanning electron microscopy and energy dispersive spectroscopy analysis. Scale-up trails have also been carried out in a solar-baffled fixed-bed reactor for the degradation of pollutant to seek the commercial viability of the technique.

-Cement and clay beads coated with TiO 2 were used for the photo-degradation and mineralization of 2-chloro-4-nitrophenol (2Cl4NP) along with a heterogeneous solar photo-Fenton process using foundry sand (FS) as the iron source. The degradation process was optimized using slurry photocatalysis where 96% degradation of 2Cl4NP was achieved in 120 min at optimized conditions of C0=50 mgL -1 , pH=4, 0.75 gL -1 TiO 2 and H 2 O 2 = 0.1 mL/200 mL. Degradation of 2Cl4NP was analyzed through HPLC along with UV-Visible spectrophotometer at 266 nm. The degradation of 68% and 52% of 2Cl4NP was attained in fixed-bed photocatalysis using cement and clay beads, respectively. The durability studies of cement and clay beads were carried out in terms of number of recycles. 97.19% degradation was obtained in a solar photo-Fenton process after 105 min at pH=3. Complete mineralization of 2Cl4NP was confirmed through reduction in COD along with the disappearance of the parent compound peak in HPLC chromatograms.

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