Liliana Amaral Féris

Degradation of Caffeine by Advanced Oxidative Processes: O3 and O3/UV

The degradation of caffeine by ozone was investigated in this article. In the laboratory experimental scale, the effect of pH, caffeine initial concentration, power UV light and reaction time were studied by experimental design. The use of response surface methodology (RSM) allowed to adjust the optimal regions of the parameters leading to the response factor (% mineralization). In addition, a single polynomial expression for modeling the reaction was obtained. Results clearly demonstrated that caffeine is quickly degraded, but not mineralized as quickly. The results indicated that the caffeine mineralization rate increased with pH and reaction time. Power UV light showed little effect on mineralization efficiency.

Comparison of different advanced oxidation processes for the removal of amoxicillin in aqueous solution

ABSTRACT Amoxicillin (AMX) is a widely used penicillin-type antibiotic whose presence in the environment has been investigated. In this work, the degradation of the AMX in aqueous solutions by ozonation, ozonation with UV radiation (O3/UV), homogeneous catalytic ozonation (O3/Fe2+) and homogeneous photocatalytic ozonation (O3/Fe2+/UV) was investigated. The performance results have been compared in terms of removal of amoxicillin and total organic carbon (mineralization efficiency). In all processes, complete amoxicillin degradation was obtained after 5 min. However, low mineralization was achieved. For the best available process, the potential toxicity of AMX intermediates formed after ozonation was examined using a Fish Embryo Toxicity test. Results reveal that O3 in alkaline solution and O3/Fe2+/UV provide the highest mineralization rates. Ecotoxicity showed that no acute toxicity was observed during the exposure period of 96 h.

Electrochemical regeneration of phenol-saturated activated carbon – proposal of a reactor

ABSTRACT An electrochemical process was used to investigate the activated carbon regeneration efficiency (RE) saturated with aromatics. For this purpose, an electrochemical reactor was developed and the operational conditions of this equipment were investigated, which is applied in activated carbon regeneration process. The influence of regeneration parameters such as processing time, the current used, the polarity and the processing fluid (electrolyte) were studied. The performance of electrochemical regeneration was evaluated by adsorption tests, using phenol as adsorbate. The increase in current applied and the process time was found to enhance the RE. Another aspect that indicated a better reactor performance was the type of electrolyte used, showing best results for NaCl. The polarity showed the highest influence on the process, when the cathodic regeneration was more efficient. The electrochemical regeneration process developed in this study presented regeneration capacities greater than 100% when the best process conditions were used, showing that this form of regeneration for activated carbon saturated with aromatics is very promising. GRAPHICAL ABSTRACT

Hospital and Municipal Wastewater: Identification of Relevant Pharmaceutical Compounds.

  The interest in the presence of pharmaceutical compounds (PhC) in the environment has increased significantly because of their potential impact on human health. Many studies have demonstrated that PhCs can be found in hospital and municipal wastewaters, mainly due to the inefficiency of the treatment plants. However, the question is how significant the hospital contribution represents in the total municipal wastewater generated. Therefore, the objective of this paper is to perform a comparison between hospital and municipal wastewaters based on literature review, serving as a base for the implementation of more efficient management policies in hospitals and municipal wastewater treatment plants. Results indicate that there are some compounds found in higher concentrations in hospital effluents than in municipal inffluent, particularly the class of antibiotics.

Study of CaCl2 as an agent that modifies the surface of activated carbon used in sorption/treatment cycles for nitrate removal

The efficiency of the application of a chemically-modified activated carbon surface was investigated. The purpose of this study was to examine the effect of treatment with CaCl2 solution at a concentration of 2000 mg.L-1 on the sorption of nitrate ions from aqueous solutions in successive sorption/t reatment cycles. The sorbent was initially subjected to chemical treatment with CaCl2 and subsequently to the sorption process. Nine sorption cycles were performed. The concentrations of nitrate ions in the solution were measured by UV-Vis spectrophotometry before and after sorption. The results show that treatment with CaCl2 caused a significant increase in the percentage removal for each treatment step, reaching a removal rate of 80% of nitrate in the solution after nine cycles.

Determination of pharmaceutical compounds in hospital wastewater and their elimination by advanced oxidation processes

ABSTRACT This study investigates the mineralization efficiency, i.e. removal of total organic carbon (TOC) in hospital wastewater by direct ozonation, ozonation with UV radiation (O3/UV), homogeneous catalytic ozonation (O3/Fe2+) and homogeneous photocatalytic ozonation (O3/Fe2+/UV). The influence of pH and reaction time was evaluated. For the best process, toxicity and degradation efficiency of the selected pharmaceutical compounds (PhCs) were determined. The results showed that the PhCs detected in the hospital wastewater were completely degraded when the mineralization efficiency reached 54.7% for O3/UV with 120 minutes of reaction time using a rate of 1.57 g O3 h−1. This process also achieved a higher chemical oxygen demand removal efficiency (64.05%), an increased aromaticity reduction efficiency (81%) and a toxicity reduction.

Consumption-based approach for pharmaceutical compounds in a large hospital

ABSTRACT Hospital wastewater contains a great variety of pharmaceutical compounds (PhCs), mainly due to excretion by patients. These PhCs, called emerging pollutants, are not fully eliminated in treatment plants, and are consequently detected in various environmental matrices, contributing to bacterial resistance and adverse environmental impacts on water resources. This study explores a consumption-based approach to predict the contribution of PhCs to a Brazilian hospital’s wastewater. This approach identifies the consumption of major pharmaceutical classes in the studied hospital. Overall, this approach demonstrates a unique opportunity to screen PhCs used in hospitals and identify priority pollutants in hospital wastewater.

Successive cycles of sorption/regeneration for granular activated carbon in the removal of nitrate ions

AbstractGranular activated carbon was used in the sorption of nitrate ions with subsequent regeneration by assessing the capacity of the sorbent in successive cycles of sorption/regeneration (S/R). Solutions of HCl, C6H8O7, NaOH, CaCl2, as well as H2O were employed in the regeneration of activated carbon saturated with nitrate. Solution of CaCl2 was the best regenerative agent. Contact times of 30 min and 400 mL of 2,000 mg L−1 CaCl2 solution were used for regeneration. Twenty cycles of S/R, which yielded 54% nitrate removal at the end of the cycles, were possible. During regeneration, the concentration of Ca2+ in the solution of CaCl2 was monitored to keep the initial concentration constant. After 20 S/R cycles, the sorbent was desorbed using 50 mL of 100 mg L−1 HCl and 50 mL H2O (60°C). Over 20 S/R cycles were performed for the sorbent recovered with HCl and 20 S/R cycles for the sorbent desorbed with H2O (60°C). Approximately 58% of nitrate removal was achieved at the end of 20 S/R cycles in both cases...

Degradation of Acid Black 210 by advanced oxidative processes: O3 and O3/UV

ABSTRACT Acid Black 210 (AB-210) dye is one of the most black dyes used by the leather industry. In the present work, AB-210 degradation in aqueous solution by ozonation (O3) and ozonation with ultraviolet (UV) radiation (O3/UV) was investigated. The effects of pH, initial dye concentration and UV radiation were studied in laboratory scale. Removal was evaluated in terms of residual AB-210 concentration in the treated solution and mineralization efficiency was evaluated by total organic carbon (TOC) analysis. The results indicated that AB-210 is quickly degraded after 15 min but not totally mineralized. It was observed that dye removal of 100% was achieved at pH 3, 7, and 11, while mineralization was found to increase with the pH (55% at pH 11). Concerning UV-C radiation, it enhanced AB-210 degradation at pH 3 but did not reveal any significant effect at pH 7 and 11.

Equilibrium studies, kinetics and thermodynamics of anion removal by adsorption

In this work, granular activated carbon (GAC) functionalised with CaCl2 was used to remove nitrate and sulphate from aqueous solutions. Functionalisation with CaCl2 influenced the physico-chemical properties and improved the adsorption capacity of activated carbon. The effect of pH on adsorption was investigated, and no significant difference was observed. The adsorption process was found to be of an exothermic nature. Thermodynamic parameters were calculated including the change in Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). The pseudo-first-order model, pseudo-second-order model and Elovich equation were used to study the adsorption kinetics. The intraparticle diffusion model, Boyds model and Banghams equation were investigated to determine the mechanism of this process. The data showed that nitrate adsorption on activated carbon follows second-order kinetics, whereas that of sulphate follows first-order kinetics. The control mechanism for the two components was determined to be particle diffusion.