Propranolol degradation through processes based on the generation of hydroxyl free radical

Pharmaceutical substances such as propranolol (PRO) are an emerging class of aquatic contaminants that have increasingly been detected in ground and surface water. For this reason, the aim of this study was to evaluate the efficiency of advanced oxidation systems for the PRO degradation. The tests started with anodic oxidation (AO), using 0.01, 0.05, and 0.1 M Na2SO4 as the supporting electrolyte and 16, 32, 48, and 64 mA cm−2 as current density. Under the best conditions obtained in AO, the electro-Fenton (EF) process was reviewed, where the effect of Fe2+ was analyzed with 5, 10, 15, and 20 mg Fe2+ L−1. The Fenton reaction (FR) was studied using the Fe2+ concentration that promoted the highest percentage of PRO removal and initial concentration of 16 mg L−1 of H2O2, in addition to these conditions, in the photo-Fenton (PF) system, the effect of UV light with wavelengths 254 and 365 nm were evaluated. The results obtained showed that the degradation efficiency of the EF > AO > PF > FR system along with a percent removal of 94.52, 90.4, 25.97, and 4.4%, respectively. The results showed that PRO can be removed through the studied systems, with the EF system being the most efficient.

Adsorption Of Methylene Blue By Imperata Cylindrica: Reaction Optimization By Response Surface Methodology (RSM)

Imperata Cylindrica (IC) is a solid waste that is readily available throughout the year known as one of the most important weed in the world and frequently causes major disposal issues. As a result, using IC as a low-cost adsorbent is beneficial from both, economic and environmental standpoint to remove colors from wastewater of textile industry. This work studies the reaction optimization of methylene blue (MB) removal using IC by response surface methodology (RSM). The RSM experiments were designed with 4 independent variables (initial adsorbent dosage, initial pH, initial dye concentration, and initial temperature) and 1 response variable (percent removal of MB). According to the pareto figure, the initial pH demonstrated the greatest impact on the percent removal of MB. The RSM data predicted the optimum condition of MB removal up to 86.61% using IC, by utilizing adsorbent dosage of 1.458 g/L, at 42 oC, initial pH of 6.8 and MB concentration of 235 ppm. The chacterization analysis revealed the physicochemical properties of IC in the adsoprtion process.

Removal of Parasite Transmission Stages from Berries Using Washing Procedures Suitable for Consumers

Due to the delicate nature of berries and the reduced shelf-life once washed, producers usually do not wash berries. Therefore, consumers are expected to wash the berries prior to consumption, and this might be a more effective way of infection prevention. However, the efficacy of consumer berry-washing procedures in removing the parasite contaminants from the berries surface has not been investigated. The aim of the present study was, therefore, to compare the efficacy of three different washing techniques in removing parasite contaminants. Three alternatives to washing berries before consumption were compared on berries artificially contaminated with oo/cysts of Cyclospora cayetanensis, Cryptosporidium parvum, and Giardia duodenalis. The results show that simple washing of berries under the cold tap for 1 min could remove on average at least 80% of the parasites, except for C. cayetanensis, which seems to be stickier than both G. duodenalis and C. parvum. The percent removal was slightly lower for raspberries as compared to blueberries. Although the differences are expected, a relevant result of the study is that washing contaminated berries prior to consumption by the consumer removes a considerable proportion of parasites and thereby lowers the risk of ingesting parasites’ transmission stages.

Adsorption of Mercury Using Different Types of Activated Bentonite: A Study of Sorption, Kinetics, and Isotherm Models

Mercury is a hazardous element because of its toxicity and harmful effects on human health. Various traditional and low-cost methods have been developed to remove mercury from wastewater. This study used local raw material as an alternative adsorbent to treat mercury-contaminated wastewater. Activated bentonite was prepared using different chemical activators (H3PO4, HCl, and ZnCl2) in various concentrations. Then, it was dried at 200°C for an hour. The materials were characterized by SEM-EDS. Its percent removal and isotherm models were analyzed. In this study, the most effective activator was H3PO4 and the experimental data matched the Freundlich model.

Decolorization of Methylene Blue Dye Using ZnO/ZSM-5 Photocatalyst Under UV-LED Irradiation

<span id="docs-internal-guid-710aacff-7fff-63c8-d621-c027e79f6f4f"><span><strong>ABSTRACT. </strong></span><span>The present research studied about decolorization of methylene blue dye using photocatalyst ZnO/ZSM-5 under UV-LED lamp. ZnO/ZSM-5 was synthesized using the impregnation method by adding two grams ZSM-5 to Zn solution 0.3 M 10 mL. Photocatalyst was characterized using X-ray diffractometer (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy-energy dispersive X-Ray (FESEM-EDX), and surface area analyzer (SAA). Analysis using XRD show addition characteristic peaks of ZnO at 2θ 31.60°, 34.21°, 36.08°, 47.35°, 56.50°, 62.73°, 67.83°, that indicates a successful impregnation process. The photocatalysis activity test was done on methylene blue dye 100 mg L-1. ZSM-5 and ZnO activities were tested under UV-LED irradiation and dark conditions. Data showed that percent removal of dye occurred on ZnO/ZSM-5 under 15 minutes irradiation is 78.32%.</span></span>

Decolorization of Methylene Blue Dye Using ZnO/ZSM-5 Photocatalyst Under UV-LED Irradiation

<span id="docs-internal-guid-710aacff-7fff-63c8-d621-c027e79f6f4f"><span>The present research studied about decolorization of methylene blue dye using photocatalyst ZnO/ZSM-5 under UV-LED lamp. ZnO/ZSM-5 was synthesized using the impregnation method by adding two grams ZSM-5 to Zn solution 0.3 M 10 mL. Photocatalyst was characterized using X-ray diffractometer (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy-energy dispersive X-Ray (FESEM-EDX), and surface area analyzer (SAA). Analysis using XRD show addition characteristic peaks of ZnO at 2θ 31.60°, 34.21°, 36.08°, 47.35°, 56.50°, 62.73°, 67.83°, that indicates a successful impregnation process. The photocatalysis activity test was done on methylene blue dye 100 mg L-1. ZSM-5 and ZnO activities were tested under UV-LED irradiation and dark conditions. Data showed that percent removal of dye occurred on ZnO/ZSM-5 under 15 minutes irradiation is 78.32%.</span></span>

Modeling and simulation of the hollow fiber bore size on the CO2 absorption in membrane contactor

Natural gas is one of the main sources of energy. It contains mainly methane and less percentage of impurity compound (CO2, H2S, and N2). The existence of these undesired impurity compounds in natural gas are not needed, because the presence of the acid gases in natural gas can cause corrosion and lowering the heating value in addition to their hazardous nature. The compound severely influenced human health and cause global warming. Accordingly, the capture of the acid gases species (i. e., CO2, H2S) from natural gas is essential. There are many techniques used for this purpose, hollow fiber polymeric membrane is a promising technique for this purpose. In this article, a numerical model is developed to study the effect of membrane contacting process with diverse fiber bore diameters on the percent removal of CO2 from a gas mixture by means of aqueous MEA/water solution as a scrubbing solvent. The developed model is validated utilizing data available in literature. The verified model is used to investigate the effect of flow rate of liquid and gas, and membrane total contact area on the CO2 removal efficiency. Results revealed that, membrane bore diameter and liquid flow rate have strong impact on the percent removal of CO2. The membrane with smaller bore diameter performs better than the other modules with greater diameter.

Pengolahan limbah cair tahu menjadi air bersih dengan metode elektrokoagulasi secara kontinyu

The liquid waste of the tofu industry contains high organic contaminants, such as proteins and amino acids. These organic compounds causes liquid waste of tofu industry to contain high BOD, COD, and TSS so that it can pollute the environment. Therefore, tofu liquid should be removed first by electrocoagulation method. This method has the potential to purify tofu liquid waste and decrease the content of COD, BOD, TSS, and pH contained without the addition of coagulants. The purpose of this study was to determine the effect of voltage and flow rate to neutralize pH, and reduce levels of COD, BOD, and TSS in tofu liquid waste. The parameters tested included COD, BOD, TSS, and pH. The electrocoagulation process uses electrical power that flows in the direction of the electrode. The electrocoagulation reactor was paired with a cable connected to the power supply then connected to an electric current with voltage and flow rate variations. The results of this study found that optimum conditions were obtained at current of 12 V and flow rate of 0.087 L/min with increasing pH from pH from 3.5 to 6.7, percent removal of COD 72.17%, percent removal BOD 71.53% , and percent removal TSS 90.90%.

Heavy Metal(loid) Remediation Using Bio-Waste

Heavy metal(loid)s are hazardous, biologically non-essential, non-biodegradable and persistent in nature, which can accumulate in plants and animals as well as in environment especially agri- and aqua- culture ecosystems. It is severely responsible for causing several health hazards problems in human, such as, cardiovascular, pulmonary, hepatic, nephrological, dermatological, neurological disorders as well as carcinogenic effects. Removal of these heavy metals from living systems is extensively expensive and also unsuccessful in sent percent removal. Therefore, in order to protect the environment, the removal of heavy metal(loid)s from polluted effluents is essential before discharging into environment. Besides various treatment technologies, sorption of metal(loid)s using bio-wastes are highly potent alternatives in recent years. The present chapter deals with the removal efficiencies of various bio-wastes, orange peels, waste tea leaves, rice husk, wheat stalk, sugar cane bagasse, coconut husk, sun flower stalk, corn cob, nut shell, water hyacinth, crab shell particle, activated carbons etc. The present discussion has also revealed that bio-waste could be a low-cost eco-friendly and green emerging alternative technology in treating the metal(loid)s contaminated environment without posing any further adverse environmental impacts.

Promoting Effect of H+ and Other Factors on NO Removal by Using Acidic NaClO2 Solution

In this study, NaClO2 was selected as a denitration oxidant. In order to clarify the mechanism of NaClO2 as an oxidation agent for NO removal efficiency, the effects of H+ and other factors (NaClO2 concentration, temperature, and the other gas) on the NO removal efficiency were investigated. NaClO2 showed a promotional ability on NO removal, whose efficiency increased with the increase of NaClO2 concentration. One hundred percent removal efficiency of NO could be achieved when the NaClO2 concentration was 0.014 mol/L. Furthermore, raising the reaction temperature benefited the removal of NO. The lower the pH, the better the NO removal efficiency. The promoting effect of H+ on the NO removal was studied by the Nernst equation, ionic polarization, and the generation of ClO2. Under the optimal conditions, the best removal efficiency of NO was 100%. Based on the experimental results, the reaction mechanism was finally speculated.