Biochar derived from pomegranate peel at different pyrolysis temperatures (450, 600, and 850 °C) was synthesized and characterized by BET, XRD, FTIR, and SEM-EDX. Its catalytic efficiency in the degradation of the antihypertensive losartan (LOS) in the presence of sodium persulfate was examined. The biochar pyrolyzed at 850 °C exhibited higher catalytic activity, which was correlated with the greater surface area and higher concentration of minerals on its surface. Interestingly, despite adsorption being favored at alkaline pH, pH 3 showed the highest LOS degradation. LOS decomposition followed pseudo-first-order kinetics. The addition of persulfate significantly increased LOS reduction, while the presence of inorganic and organic water matrix constituents such as sodium chloride, bicarbonate, and humic acid inhibited the oxidation. Experiments conducted with radical scavengers revealed that both hydroxyl and sulfate radicals, as well as singlet oxygen, participated in LOS decomposition, with the former being the dominant species. Using a continuous flow reactor, the system exhibited a satisfactory steady-state performance of 90% LOS removal for 114 h. Afterward, a moderate decrease in performance was observed, which can be attributed to the alteration of the catalyst’s surface and mineral dissolution due to acidity.

The pursuit of low-cost, high-efficiency co-catalysts that are free of noble metals has become an area of considerable interest in the field of photocatalysis over the past few years. In this work, a series of cobalt phosphide (CoP 0.125–1.00 wt.%)-promoted bismuth vanadate (BiVO₄) photocatalysts was synthesized and physicochemical characterized by means of X-Ray diffraction, nitrogen isotherm absorption diffuse-reflectance spectroscopy, and high-resolution transmission electron microscopy. The efficiency of the as prepared photocatalytic materials was investigated for sulfamethoxazole (SMX) destruction in ultrapure water under simulated solar light irradiation. Results showed that the deposition of small amounts (0.50 wt.%) of CoP on BiVO₄ enhances SMX degradation. Moreover, SMX removal increased by increasing 0.50 CoP/BiVO₄ loading (up to 1 g/L) and decreasing SMX loading (1000–250 μg/L). Further tests were carried out in real and synthetic matrices, such as wastewater secondary effluent and bottled water, revealing the existence of hindering effects on SMX removal. The efficiency of 0.50 CoP/BiVO₄ photocatalyst was further investigated in a pilot plant configuration where the examined system was able to remove >99% of 300 μg/L SMX in deionized water utilizing 80 kJ/L of solar irradiation.

In this study, spent malt rootlet-derived biochar was modified by a friendly eco-method using a low temperature (100 °C) and dilute acid, base, or water. The modification significantly enhanced the surface area from 100 to 308–428 m²g⁻¹ and changed the morphology and the carbon phase. In addition, the mineral’s percentage and zero-point charge were significantly affected. Among the examined materials, the acid-treated biochar exhibited higher degradation of the drug losartan in the presence of persulfate. Interestingly, the biochar acted as an adsorbent at pH 3, whereas at pH = 5.6 and 10, the apparent kinetic constant’s ratio k_oxidation/k_adsorption was 3.73 ± 0.03, demonstrating losartan oxidation. Scavenging experiments indirectly demonstrated that the role of the non-radical mechanism (singlet oxygen) was crucial; however, sulfate and hydroxyl radicals also significantly participated in the oxidation of losartan. Experiments in secondary effluent resulted in decreased efficiency in comparison to pure water; this is ascribed to the competition between the actual water matrix constituents and the target compound for the active biochar sites and reactive species.

The solar-induced semiconductor photocatalytic process is one of the greenest and most promising technologies for the elimination of pharmaceuticals in aqueous media. In the context of this study, a bismuth oxychloride (BiOCl) photocatalyst was fabricated and characterized by its morphology, crystallographic structure, and optical properties. Its photocatalytic efficiency was tested towards the degradation of Losartan (LOS), a medication used to treat high blood pressure, in water using a solar simulator. The as-prepared BiOCl exhibited significant photocatalytic efficiency, achieving complete degradation of 0.3 mg/L LOS in short periods of irradiation (15–30 min). The examined system showed optimal efficiency using 500 mg/L of BiOCL (k_app = 0.21 min⁻¹) and pH 3 (k_app = 0.32 min⁻¹). However, LOS removal significantly decreased in environmentally relevant water matrices, including wastewater (k_app = 0.006 min⁻¹) and bottled water (k_app = 0.023 min⁻¹). Additional tests carried out in synthetic water matrices showed that the LOS degradation rate was reduced by more than 40% in the presence of humic acid (k_app = 0.016 min⁻¹) and bicarbonates (k_app = 0.029 min⁻¹), while chlorides did not affect the overall efficiency. Moreover, photogenerated holes and singlet oxygen were the dominant oxidative species. The efficiency of the BiOCl photocatalyst towards LOS degradation was further studied using a flat plate pilot-plant scale photoreactor. It was found that more than 75% of LOS was removed after 100 kJ/L of accumulated solar irradiation. The results obtained in the pilot-plant unit confirmed the suitability of BiOCl as a potential photocatalytic material.

In this work, the decomposition of bisphenol S (BPS) by biochar derived from banana peel (BPB) promoted by copper phosphide (Cu₃P) was examined. Different materials with Cu₃P loadings from 0.25 to 4.00 wt.% on biochar were synthesized, characterized using the Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD) and a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS), and evaluated. Nearly all of the synthesized materials exhibited low to moderate adsorption capacity, attributable to their limited surface area (<3.1 m²/g). However, in the presence of sodium persulfate (SPS), the 2%Cu₃P/ΒPB/SPS system was capable of removing 90% of 500 μg/L BPS in less than 10 min. The system’s performance was enhanced under inherent pH, and the reaction rate followed pseudo-first-order kinetics with respect to BPS and persulfate concentrations. Interestingly, the presence of 250 mg/L of sodium chloride had a negligible effect, while low to moderate inhibition was observed in the presence of bicarbonates and humic acid. In contrast, significant retardation was observed in experiments performed in real matrices, such as secondary effluent (WW) and bottled water (BW). According to scavenging experiments, both radical and non-radical mechanisms participated in the BPS degradation. Four transformation products were identified using the UHPLC/TOF-MS system in negative ionization mode, with two of them having higher molecular weights than BPS, while the other two TBPs involved the ring-opening reaction, and a BPS decomposition pathway was proposed.

This work examines the solar photocatalytic degradation of the antibiotic sulfamethoxazole (SMX) using molybdenum telluride (MoTe₂)-promoted bismuth oxychloride (BiOCl). Different loadings of molybdenum telluride in the 0–1% range on BiOCl were synthesized and evaluated. Although the presence of MoTe₂ did not alter either the adsorption capacity or the energy gap of BiOCl, the synthesized photocatalyst demonstrated higher photocatalytic activity due to the enhanced separation of photogenerated pairs. The 0.5MoTe₂/BiOCl photocatalyst achieved a kinetic constant nearly 2.8 times higher than that of pure BiOCl, leading to the elimination of 500 μg/L SMX within 90 min. The system’s performance was enhanced under neutral to acidic conditions and lower SMX concentrations. Based on experiments with radical scavengers, photogenerated holes appeared to be the dominant species, with the contribution of reactive species following the order ${\mathrm{h}}^{+}>{\mathrm{O}}_2^{•-}/{\mathrm{e}}^{-}>$¹${\mathrm{O}}_2{>\mathrm{H}\mathrm{O}}^{•}$. Interestingly, in different water matrices, photocatalytic activity was not diminished and even increased by 20%, likely because of the action of photogenerated holes and the selectivity of secondary generated radicals. The photocatalyst retained > 90% of its activity after three sequential experiments. Finally, four transformation products from SMX photodegradation were identified via UHPLC-TOF-MS, and a degradation pathway is proposed.