Application of Pier Waste Sludge for Catalytic Activation of Proxy-monosulfate and Phenol Elimination From a Petrochemical Wastewater

This investigation aimed to remove phenol from a real wastewater (taken from a petrochemical company) by activating peroxy-monosulfate (PMS) using catalysts extracted from pier waste sludge. The physical and chemical properties of the catalyst were evaluated by FE-SEM/EDS, XRD, FTIR, and TGA/DTG tests. The functional groups of O-H, C-H, CO32-, C-H, C-O, N-H, and C-N were identified on the catalyst surface. Also, the crystallinity of the catalyst before and after reaction with petrochemical wastewater was 103.4 nm and 55.8 nm, respectively. Operational parameters of pH (3-9), catalyst dose (0-100 mg/L), phenol concentration (50-250 mg/L), and PMS concentration (0-250 mg/L) were tested to remove phenol. The highest phenol removal rate (94%) was obtained at pH=3, catalyst dose of 80 mg/L, phenol concentration of 50 mg/L, PMS concentration of 150 mg/L, and contact time of 150 min. Phenol decomposition in petrochemical wastewater followed the first-order kinetics (k> 0.008 min-1, R2> 0.94). Based on the reported results, it was found that the pH factor is more important than other factors in phenol removal. The catalyst stability test was performed for up to five cycles and phenol removal in the fifth cycle was reduced to 42%. Also, the energy consumption in this study was 77.69 kw.h/m3. According to the results, the pier waste sludge catalyst/PMS system is a critical process for eliminating phenol from petrochemical wastewater.

The Performance of Activated Carbon from Used Coffee Grounds Combined with Iron(III) Oxide under UV Light and Ultrasound for Phenol Degradation

Coffee consumption over the past four years has continued to increase the amount of used coffee grounds. Usually, the used coffee grounds are simply thrown away. In fact, it can still be used as other materials that are more efficient and environmentally friendly, such as activated carbon. Activated carbon can be utilized as an adsorbent to adsorb compounds that are carcinogenic and potentially last a long time in the environment, such as phenols. Phenol decomposition through chemical can be carried out by Advanced Oxidation Process (AOP) which utilize hydroxyl radicals. This method used a catalyst such as iron(III) oxide under ultraviolet light. Phenol decomposition can also be carried out using ultrasound. This study presents the performance of the combination of activated carbon-catalyst with ultrasound in phenol decomposition. The results showed that the mass of the composite influenced the 0.1 M phenol degradation by the activated carbon–iron(III) oxide assisted with ultraviolet light, ultrasound, and 0.01 M hydrogen peroxide. for 45 minutes. The best degradation of phenol was obtained when 0.5 g adsorbent was applied with the adsorption capacity of phenol was 704.37 mg/g. The concentration of hydrogen peroxide also affects the decomposition of phenol in solution. From the variation of the hydrogen peroxide solution used (0.01; 0.02; and 0.03 M), the optimal concentration in degrading phenol was 0.01 M with the adsorption capacity of phenol was 393.70 mg/g.

Removal of Phenol from Aqueous Solution Using Internal Microelectrolysis with Fe-Cu: Optimization and Application on Real Coking Wastewater

Fe-Cu materials were synthesized using the chemical plating method from Fe powder and CuSO4 5% solution and then characterized for surface morphology, composition and structure by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The as-synthesized Fe-Cu material was used for removal of phenol from aqueous solution by internal microelectrolysis. The internal electrolysis-induced phenol decomposition was then studied with respect to various parameters such as pH, time, Fe-Cu material weight, phenol concentration and shaking speed. The optimal phenol decomposition (92.7%) was achieved under the conditions of (1) a pH value of phenol solution of 3, (2) 12 h of shaking at the speed of 200 rpm, (3) Fe-Cu material weight of 10 g/L, (4) initial phenol concentration of 100.98 mg/L and (5) at room temperature (25 ± 0.5 °C). The degradation of phenol using Fe-Cu materials obeyed the second-order apparent kinetics equation with a reaction rate constant of k of 0.009 h−1L mg−1. The optimal process was then tested against real coking wastewater samples, resulting in treated wastewater with favorable water indicators. Current findings justify the use of Fe-Cu materials in practical internal electrolysis processes.

Removal efficiency of phenol by ozonation process with calcium peroxide from aqueous solutions

Phenol has been introduced as a priority pollutant by the US Environmental Protection Agency. Advanced oxidation processes (AOPs) are one of the most efficient methods for removal of non-degradable organic pollutants in aqueous solutions. The removal efficiencies of phenol and COD under optimal conditions pH = 3, phenol concentration = 5 mg/L, CaO2 concentration = 0.025 mg/L, temperature 25 °C, 1 g/min ozonation rate and contact time = 90 min in synthetic and real samples (Zarand coal washing factory in Kerman) were obtained 97.8%, 87% and 80%, 65.4%, respectively. The kinetics of phenol decomposition follows from the pseudo-first-order equation. Thermodynamic studies show that phenol decomposition with ozonation and calcium peroxide is an endothermic process. The use of ozonation process with calcium peroxide is an efficient method and can be recommended as a coefficient method for the removal of phenol.

Oxidative destruction of phenol on Fe/SiO2 catalysts

In the present study, the sol-gel technique helped to obtain Fe-containing samples with a base of amorphous silicon dioxide from rice husks RH-Fe and RH-Fe-300. These materials are characterized by IR spectroscopy, X-ray phase and X-ray spectral analysis. It was shown that the samples contain silicate structures Si-O-Si(Fe) and are in an amorphous state. Structure of the surface layers of RH-Fe-300 catalyst particles was established for the first time using X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectra (EDX) methods. It was shown that the surface layers of the synthesized particles are oxygen depleted due to oxygen vacancies and silanol groups, therefore defects can form in its structure. Photocatalytic activity of the samples in the phenol oxidation reaction under ultraviolet and solar irradiation in the presence of hydrogen peroxide was studied. It was shown that the degree of phenol decomposition in the presence of RH-Fe for 24 hours under solar irradiation was 92%, in the presence of RH-Fe – 17%. Under two-stage irradiation (ultraviolet and solar), the percentage of phenol decomposition using both catalysts after a day amounted to more than 80%. It was established that RH-Fe-300 catalyst increases oxidation of phenolic compounds in alkaline rice husk hydrolysates under solar irradiation in the presence of hydrogen peroxide.