Degradation of Dichloromethane Containing Laboratory Wastewater Using Photoelectric Fenton Process

Conducting laboratory experiments in educational institutions has been linked with the increased amount of chemical waste disposed in the environment. The excessive usage and disposal of Dichloromethane (DCM) has been attributed to financial and environmental concerns. This present study aimed to treat the DCM containing laboratory wastewater using Photoelectric Fenton (PEF) process. The PEF treatment was done at varying ultraviolet (UV) light intensity (3, 6 and 9 Watts), sacrificial anode (Al, Cu and TiO2), and oxidizing agent (OA) loading ratio (1.13, 3.76, and 6.39 w/w) under 30oC and 1 atm. Results have shown that the highest degradation (99.82%) of DCM was obtained at 9 Watts of UV light intensity, 3.76 w/w [H2O2]:[Fe2+] OA loading ratio, and with TiO2 coated with IrO2 and RuO2 as the anode. It was detected that higher UV light intensity favors the degradation efficiency when using the TiO2 coated with IrO2 and RuO2 anode. On the other hand, higher OA loading ratios proved to negatively affect the process as high concentrations of H2O2 become ineffectual for the degradation of organics. Finally, analysis of variance (ANOVA) showed the positive correlation between degradation efficiency and UVA light intensity.  This confirmed the applicability of the PEF process in degrading of recalcitrant pollutants in wastewater, thus showing potential for mitigating its environmental impact

A Comprehensive Review on the Drying Kinetics of Common Tubers

Sun-drying has been conventionally used in the production of tuber-derived commodities such as cassava, potato, sweet potato, and yam. Recent developments in the drying process involves the use of different drying equipment to improve quality and profitability. The importance of drying parameters in the operation of drying equipment necessitates drying kinetic studies on common tubers. This article aims to review the drying kinetics studies conducted on common tubers. Particular interest is on the effect of the drying process parameters like temperature and velocity of heating air medium, the physico-chemical pretreatment method, and sample preparation on the drying rate and time. The different best fit drying kinetic models for specific tubers have also been extensively studied. The role of drying process parameters and best fit model equations on the design of the drying equipment has been emphasized

Kinetics and Equilibrium Modeling of Single and Binary Adsorption of Aluminum (III) and Copper (II) Onto Calamansi (Citrofortunella microcarpa) Fruit Peels

The introduction of heavy metal wastes in the environment has posed health risks to both human and animals due to their toxicity. Since then, different studies have been explored for the possibility of utilizing new, low–cost, and sustainable adsorbent materials to get rid of heavy metals in the wastewater streams and aqueous solutions. This present study aimed to investigate and compare the adsorption ability of powdered calamansi (Citrofortunella microcarpa) fruit peels (PCFP) for the elimination of both Al(III) and Cu(II) ions in single (non–competitive) and binary (competitive) aqueous systems by batch adsorption techniques. Scanning electron microscopic and spectroscopic techniques were used to characterize the surface morphologies for the biosorbent and quantify the removal rates of heavy metal, respectively. Models were then used to describe in detail about the adsorption kinetics and isotherms for both single and binary metal systems. The influence and dependency of different experimental conditions on adsorption performance were also analyzed. The PCFP derived biosorbent was successful in removal of both Al(III) and Cu(II) ions in single (non–competitive) and binary (competitive) aqueous systems with 99, 70 and 91% adsorption rates, respectively. The biosorption process follows the Ho’s pseudo–second order kinetics. Furthermore, the Langmuir isotherm model was found helpful in explaining the adsorption mechanism. The dominating electrostatic interaction between adsorbents and adsorbates demonstrates monolayer adsorption at the binding sites on the surface of the peeling. Finally, the findings of this study will contribute to a better understanding of the adsorption process, as well as future system design applications in the treatment of heavy metal containing waste effluents

Synergy of in-situ formation of carbonic acid and supercritical CO2-expanded liquids: Application to extraction of andrographolide from Andrographis paniculata

The environmental impact of excessive solvent usage in the pharmaceutical industry has generated research interests in the area of green and sustainable extraction processes. In this study, solvent minimization was done by exploiting the synergistic effect of pH lowering (via in-situ H2CO3 formation) and solvent\u27s volume expansion (via CO2-expanded solvent) in the extraction of andrographolide from Andrographis paniculata. Conventional solid-liquid extraction (CSLE) and CO2-expanded liquid extraction (CXLE) were conducted using different solvents at a pressure range of 0.1–10 MPa and 40 °C in a batch-type extraction vessel to verify both the independent and combined effect of pH and the solvent\u27s volume expansion coefficient (V/V0) in the extraction recovery. Also, fresh and spent biomass were analyzed using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) in order to assess the physical impact of the extraction scheme. The highest andrographolide recovery of 65% was obtained using CXLE with ethanol and water at pH = 3.02 and V/V0 = 4.8, owing to the synergistic effects of the two variables. Furthermore, an increase in extraction recovery with decreasing pH and increasing V/V0 was observed. Moreover, a significant morphological difference between the fresh and spent samples was observed from the results of characterizations, indicating a disruption in the cell wall associated to the expansion of the solvent as it penetrated the plant matrix. The proposed novel extraction strategy allowed a high extraction recovery of andrographolide while complying with sustainable and green practices. © 2019 Elsevier B.V

Ultrasound-Assisted Biomimetic Synthesis of Mof-Hap Nanocomposite via 10xsbf-Like for the Photocatalytic Degradation of Metformin

High levels of emerging pollutants, such as pharmaceutical compounds like metformin (MET), have been an issue for many years. The effective removal of these compounds from wastewater poses a significant challenge and has spurred interest among researchers. This study aims to integrate two of the prominent research interests in photocatalysis, Metal-Organic Frameworks (MOF), and Hydroxyapatite (HAp), and tests their effectiveness in the photocatalytic degradation of MET. The MOF-HAp was produced using a biomimetic method via 10xSBF-like solution with and without ultrasound assistance at varying biomimetic times. MOF-HAp nanocomposite’s photocatalytic degradation capabilities were tested by degrading MET, considering varying parameters – initial pollutant concentration, catalyst loading, and exposure time. Results showed that a biomimetic time of 6 h synthesized with ultrasound irradiation presented the most promising physicochemical properties for MOF-HAp, as verified by the X-ray Fluorescence (XRF), Scanning Electron Microscope (SEM), Brunauer-Emmett-Teller (BET), X-ray Diffractometer (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) analyses. In the photocatalytic degradation of MET, catalyst loading, exposure time, and initial pollutant concentration were found to have significant effects on the percent degradation. The initial concentration of 8 ppm, catalyst loading of 0.25 g, and 120 min of exposure time produced the highest percent degradation with an average of 82.25%. The findings of this study prove MOF-HAp's potential to effectively degrade organic and pharmaceutical pollutants in wastewater