Optimization of ethanol-modified subcritical water extraction of curcuminoids from turmeric (Curcuma longa L.) rhizomes: Comparison with conventional techniques.

Subcritical solvent extraction (SSE) as ethanol-modified subcritical water extraction (SWE) was applied to extract curcuminoids from turmeric (Curcuma longa L.) rhizomes. RSM-CCD was employed to evaluate the influential factors including temperature (90-150 °C), flow rate (1-4 mL/min), and ethanol concentration (25-75 wt%) on the extraction yield. The optimum condition was 90 °C, 4 mL/min, and 25 wt% with the extraction yield of 4.12 wt% (db). Applying ethanol as a polarity-tuning parameter enabled operations at lower temperatures, which prevented thermal degradation. The SSE optimum experiment was compared with Soxhlet, ultrasound-assisted extraction (UAE) and conventional solvent extraction (CSE), both with the ethanol-water mixture (25 wt%). Their yields were 2.71, 0.85, and 0.84 wt% (db), respectively. The higher yield of SSE was related to the higher solubility of curcuminoids due to the more appropriate adjustment of solvent polarity by a decrease in the dielectric constant with a rise in the operating temperature.

Elimination of amoxicillin using zeolite Y-sea salt as a good catalyst for activation of hydrogen peroxide: Investigating degradation pathway and the effect of wastewater chemistry.

The sea contains elements that can play a useful role in catalyzing reactions. Therefore, this research was done to focus on eliminating amoxicillin (AMX) from wastewater utilizing zeolite Y- sea salt catalyst in the presence of H2O2. The influences of furnace temperature (200-500 °C) and time duration in the furnace (1-4 h) were optimized during catalyst generation. Also, the effects of different parameters on AMX removal, such as pH (5.0-9.0), catalyst dose (0-10 g.L-1), AMX concentration (50-300 mg.L-1), contact time (10-130 min), and H2O2 concentration (0-6 mL/100 mL distilled water) were investigated. Different analyses like Brunauer-Emmett-Teller (BET), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were conducted to reveal catalyst properties. The BET-specific surface area of the catalyst (12.69 m2g-1) insignificantly (p-value > 0.05) changed after AMX removal (13.04 m2g-1), indicating the strength of the prepared catalyst. The active groups of N-H, O-H-O, O-Si-O, C-H, Si-O-Si, and Si-O-Al were determined in the catalyst structure. The highest removal of AMX (93%) was achieved in the zeolite-sea salt/H2O2 system at a pH level of 6.0 and an H2O2 concentration of 0.1 mL/100 mL. Elimination of the AMX followed pseudo-first-order kinetics. The catalyst was reclaimed up to 7 times and the removal efficiency was suitable up to the fifth stage. The by-products and reaction pathways were investigated by gas chromatography-mass spectrometry (GC-MS). The results showed that zeolite-sea salt can be utilized as an H2O2 activator for the effective degradation of AMX from wastewater.

Removal of amoxicillin from wastewater in the presence of H2O2 using modified zeolite Y- MgO catalyst: An optimization study.

In this paper, Zeolite-MgO was generated using alkali-thermal method and was utilized as a catalyst to decrease amoxicillin (AMX) concentration in the presence of H2O2 from wastewater. Different tests like Fourier-transform infrared (FTIR), Brunauer-Emmett-Teller (BET), field emission scanning electron microscopy-energy dispersive X-ray analysis (FESEM-EDX), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) were done to determine catalyst properties. Active groups of C-S-C, CO, CC, C-N, C-O, N-O, and N-H were identified in catalyst frame. According to XRD results, lower crystallinity of nanoparticles after modification of zeolite by MgO can lead to improvement of AMX removal. Active surface of zeolite (2.32 m2/g) was increased after optimization by MgO to 2.96 m2/g, indicating an increase in the catalyst capacity for activation of H2O2. In addition, furnace temperature (200-500 °C), residence time in the furnace (1-4 h), and Mg(NO3)2: zeolite ratio (0.25: 2, 0.5:2, 1:2 w/w) were studied to achieve the optimized catalyst for AMX removal. Different parameters like pH (5-9), H2O2 concentration (0-6 mL/100 mL), dose of catalyst (0-10 g/L), AMX concentration (50-300 mg/L), and reaction time (10-130 min) were also studied. The best efficiency (97.9%) of AMX removal was achieved at acidic pH with the lowest amount of H2O2 (0.1 mL/100 mL) and 7 g/L of catalyst. AMX removal using the developed process followed pseudo-first-order kinetics. Reclaimable Zeolite-MgO catalyst can be effectively utilized in wastewater works.