Effective method of treatment of industrial effluents under basic pH conditions using acoustic cavitation – A comprehensive comparison with hydrodynamic cavitation processes

The use of acoustic cavitation in advanced oxidation processes (AOPs) is a promising trend in research for treatment of industrial effluents. The paper presents the results of investigations on the use of acoustic cavitation aided by additional oxidation processes (ozonation/H2O2 oxidation/Peroxone/UV-C) for the treatment of effluents from the production of bitumens. Under these conditions, the total contaminant load, expressed as chemical oxygen demand (COD), could be lowered by 51%. In addition, changes in concentrations of volatile organic compounds identified in the effluents following the treatment are discussed. The investigations revealed that by using acoustic cavitation combined with the Peroxone process, the majority of oxygenated organic compounds were oxidized. The paper also compares AOPs based on acoustic cavitation with hydrodynamic cavitation-aided processes. This study revealed that the use of acoustic cavitation results in a higher effectiveness of degradation of organic compounds using AOPs based on hydrogen peroxide. On the other hand, hydrodynamic cavitation is generally a slightly more effective method for degradation of organic compounds for ozone-based AOPs. Furthermore, furfural and 2-methylcyclohexanone were discovered as secondary pollutants whose concentration increased during the treatment

Highly effective degradation of selected groups of organic compounds by cavitation based AOPs under basic pH conditions

Cavitation has become on the most often applied methods in a number of industrial technologies. In the case of oxidation of organic pollutants occurring in the aqueous medium, cavitation forms the basis of numerous advanced oxidation processes (AOPs). This paper presents the results of investigations on the efficiency of oxidation of the following groups of organic compounds: organosulfur, nitro derivatives of benzene, BTEX, and phenol and its derivatives in a basic model effluent using hydrodynamic and acoustic cavitation combined with external oxidants, i.e., hydrogen peroxide, ozone and peroxone. The studies revealed that the combination of cavitation with additional oxidants allows 100% oxidation of the investigated model compounds. However, individual treatments differed with respect to the rate of degradation. Hydrodynamic cavitation aided by peroxone was found to be the most effective treatment (100% oxidation of all the investigated compounds in 60 min). When using hydrodynamic and acoustic cavitation alone, the effectiveness of oxidation was diversified. Under these conditions, nitro derivatives of benzene and phenol and its derivatives were found to be resistant to oxidation. In addition, hydrodynamic cavitation was found to be more effective in degradation of model compounds than acoustic cavitation. The results of investigations presented in this paper compare favorably with the investigations on degradation of organic contaminants using AOPs under conditions of basic pH published thus far

Wastewater treatment by means of advanced oxidation processes based on cavitation – A Review

Hydrodynamic and acoustic cavitation combined with advanced oxidation processes (AOPs), including, among others, the Fenton process, is a promising alternative to the technologies of wastewater treatment technologies in use today. The present review discusses processes based on cavitation combined with AOPs and evaluates their effectiveness in oxidation of organic contaminants. Complete degradation of, among others, p-nitrotoluene, p-aminophenol, 1,4-dioxane, alachlor, chloroform, trichloroethylene, sodium pentachlorophenate and carbon tetrachloride was achieved by using hydrodynamic cavitation or acoustic cavitation alone. Cavitation is also an effective method of disinfection of water. Complete oxidation of hardly degradable organic contaminants, including pharmaceuticals, organic dyes, insecticides, phenol and its derivatives was observed when using hybrid processes: hydrodynamic or acoustic cavitation combined with the Fenton process, ozonation, hydrogen peroxide, UV irradiation, catalysts and persulfates. The review also discusses the cavitational reactors used in the wastewater treatment and the effect of process parameters (including pH, temperature, concentration and kind of contaminants) on the effectiveness of oxidation. The oxidation effectiveness for individual treatment methods is compared and their advantages and limitations discussed. The analysis of economics of the treatment processes performed to evaluate the possibility of scaling up reveals that the only economical processes should be based on hydrodynamic cavitation (mainly due to low cost of reactors and low consumption of electrical energy compared with ultrasonic reactors)

Effective method of treatment of effluents from production of bitumens under basic pH conditions using hydrodynamic cavitation aided by external oxidants

Utilization of cavitation in advanced oxidation processes (AOPs) is a promising trend in research on treatment of industrial effluents. The paper presents the results of investigations on the use of hydrodynamic cavitation aided by additional oxidation processes (O 3/H 2O 2 /Peroxone) to reduce the total pollution load in the effluent from the production of bitumens. A detailed analysis of changes in content of volatile organic compounds (VOCs) for all processes studied was also performed. The studies revealed that the most effective treatment process involves hydrodynamic cavitation aided by ozonation (40% COD reduction and 50% BOD reduction). The other processes investigated (hydrodynamic cavitation + H ⁠2O ⁠2 , hydrodynamic cavitation + Peroxone and hydrodynamic cavitation alone) ensure reduction of COD by 20, 25 and 13% and reduction of BOD by 49, 32 and 18%, respectively. The results of this research revealed that most of the VOCs studied are effectively degraded. The formation of byproducts is one of the aspects that must be considered in evaluation of the AOPs studied. This work confirmed that furfural is one of the byproducts whose concentration increased during treatment by hydrodynamic cavita-tion alone as well as hydrodynamic cavitation aided by H ⁠2O ⁠2 as an external oxidant and it should be controlled during treatment processes

Effective degradation of sulfide ions and organic sulfides in cavitation-based Advanced Oxidation Processes (AOPs)

The paper presents the results of investigations on the effectiveness and reaction rate constants of the oxidation of sulfide ions and organic sulfides in real industrial effluents from the production of bitumens (2000 mg S2− L−1) using hydrodynamic and acoustic cavitation. The content of the effluents was analysed in terms carbon disulfide, dimethyl sulfide, and di-tert-butyl disulfide concentration. A possibility of complete oxidation of sulfides by cavitation alone as well as by its combination with external oxidants such as hydrogen peroxide, ozone or peroxone was demonstrated. The oxidation time for the most effective processes is as little as 15 min. Due to the presence of sulfide ions, the effluents from the production of bitumens were oxidized at a strongly alkaline pH. The results of this study reveal the advantage of performing advanced oxidation processes (AOPs) at a basic pH. The effective degradation of sulfide ions enables performance of further degradation of organic contaminants at an acidic pH, ensuring high efficiency of treatment based, for example, on the Fenton reaction without the risk of release of hydrogen sulfide to the atmosphere. The results of this research are applicable to all kinds of caustic effluents for which the lack of possibility of pH adjustment limits their efficient treatment

Hydrodynamic cavitation based advanced oxidation processes: Studies on specific effects of inorganic acids on the degradation effectiveness of organic pollutants

The use of cavitation in advanced oxidation processes (AOPs) to treat acidic effluents and process water has become a promising trend in the area of environmental protection. The pH value of effluents – often acidified using an inorganic acid, is one of the key parameters of optimization process. However, in the majority of cases the effect of kind of inorganic acid on the effectiveness of degradation is not studied. The present study describes the results of investigations on the use of hydrodynamic cavitation (HC) for the treatment of a model effluent containing 20 organic compounds, representing various groups of industrial pollutants. The effluent was acidified using three different mineral acids. It was demonstrated that the kind of acid used strongly affects the effectiveness of radical processes of oxidation of organic contaminants as well as formation of harmful secondary pollutants. One of important examples is a risk of formation of p-nitrotolune. Sulfuric acid was the only chemical used for acidification which caused effective treatment with lack of formation of monitored type of secondary pollutants. The best treatment effectiveness – during a 6-hour cavitation process - in most cases much above 80% along with 90% TOC removal was obtained in the case of sulfuric acid. Nitric acid provided lower effectiveness (above 60% for most of the compounds). The worst performance are reported for hydrochloric acid – below 50% of degradation for most of the compounds

A multivariate investigation into the relationship between pharmaceutical characteristics and patient preferences of bioequivalent ibuprofen tablets

Tatiana R Alonso,1 Adrianna Gagol,1 Maximilian Scherer,1 Antonio Matji,1 Santiago Torrado-Santiago,2 Dolores R Serrano,1 Alfredo Garcia-Arieta,3 Juan J Torrado1 1Pharmaceutics and Food Technology, School of Pharmacy, Complutense University, Madrid, Spain; 2Industrial Pharmacy Institute, Complutense University, Madrid, Spain; 3Service on Pharmacokinetics and Generics, Department of Human Use Medicines, Division of Pharmacology and Clinical Evaluation, Spanish Agency for Medicines and Health Care Products, Madrid, Spain Background: In Spain the price of all ibuprofen 600 mg tablet generic products is the same due to reimbursement existing rules so for the patient there is not any economic incentive to choose a particular one. Bearing in mind that the quality of generic products should be similar, it could be questioned if differences in patient preferences evaluated as sales could be related to differences on their pharmaceutical properties. The aims of this work were to study the variability on the pharmaceutical characteristics of marketed bioequivalent tablet formulations and its impact on patient preferences. Methods: Thirty-six batches corresponding to fourteen different generic products were chosen among the best-selling products of the Spanish market in the years 2011 and 2015 and were compared to the reference product. The effect on patient preferences of six variables was studied through a multivariate analysis. The first two variables were marketing characteristics: 1) years in the market and 2) the number of other generic products marketed by the same manufacturer, which could be related to the size and service provided by the manufacturer. The other four variables studied were pharmaceutical tablet properties: 3) mean weight, 4) hardness, 5) disintegration, and 6) dissolution. A multiple linear regression analysis was performed to identify the effect on sales of the six variables studied. Results: The disintegration time was the most significant (P=0.018) factor affecting the sales of Ibuprofen tablets which may be related to the onset of action. Conclusion: The faster the tablet disintegration, the higher its sales. Two possible explanations are suggested: 1) the most specialized ibuprofen tablet manufacturer considers fast disintegration as a key parameter and/or 2) habitual consumers of ibuprofen can detect small differences on the onset of action among different marketed formulations. In this work, all marketed ibuprofen tablets comply with the pharmacopoeia specifications. Keywords: ibuprofen, sales, disintegration, generic, multiple linear regression analysis, multivariate analysi

Predicting the critical quality attributes of ibuprofen tablets via modelling of process parameters for roller compaction and tabletting

Roller compaction is a low cost granulation process which application is sometimes limited by the granular loss of compactability and reduced drug dissolution rate. Hence, the design of a robust manufacturing process is key in order to ensure quality of tablets. In this study, for ibuprofen tablets with high drug loading (<7% excipients), the correlations between two critical process parameters (CPPs), namely roller force during granulation and compaction pressure during tabletting, and several critical quality attributes (CQAs) were investigated using a design of experiment (DoE) approach. Multivariate analysis (MVA) was utilized to identify the best regression model to predict CQAs such as disintegration, dissolution, weight uniformity, hardness, porosity and tensile strength for 200 and 600 mg ibuprofen tablets. The tabletting compaction pressure had a greater impact on the aforementioned CQAs than compactor roller force. The Principal Component Analysis (PCA) correlation loading plot showed that compaction pressure was directly related to disintegration time, tensile strength and hardness, and inversely related to both the percentage of drug dissolved and porosity. The inverse correlations were observed for the roller force applied during dry granulation. Amongst all the regression models constructed, multiple linear regression (MLR) showed the best correlation between CPPs and CQAs.We would like to thank Industrial Farmaceutica Cantabria (Torrejón, Spain) for their support and assistance to perform this work. This study was partially supported by the Complutense University of Madrid and a Science Foundation Ireland grant co-funded under the European Regional Development Fund (SFI/12/RC/2275) provided to Prof. A. M. HealyPeer Reviewe