Removal of anti-inflammatory drugs using activated carbon from agro-industrial origin: current advances in kinetics, isotherms, and thermodynamic studies

Nonsteroidal anti-inflammatory drugs (NSAIDs) are highly consumed around the world and consequently found as emerging pollutants in water; they are found in concentrations up to µg L−1 making their removal a priority. In this matter, adsorption is an efficient alternative for drug removal, so using activated carbon (AC) as an adsorbent is a highly explored subject. The current interest is to obtain AC from waste, for example, those of agro-industrial origin, reducing this way the overall costs of the process. Although information regarding the use of AC from agro-industrial origin in the removal of NSAIDs is limited, an exclusive compilation is required to understand the state of the art to date. This work aims to update information related to the adsorption of ibuprofen, diclofenac, and naproxen on agro-industrial AC, and it is focused on the period 2016–2021. It highlights the characteristics of agro-industrial AC responsible for efficient adsorption. Recent adsorption studies, including kinetics, isotherms, and thermodynamics, are analyzed and compared. Progress on removing NSAIDs from real wastewater is also presented and finally proposed adsorption mechanisms and costs related to these removal processes.

Metal-Pseudomonas veronii 2E Interactions as Strategies for Innovative Process Developments in Environmental Biotechnology

The increase of industrial discharges is the first cause of the contamination of water bodies. The bacterial survival strategies contribute to the equilibrium restoration of ecosystems being useful tools for the development of innovative environmental biotechnologies. The aim of this work was to study the Cu(II) and Cd(II) biosensing, removal and recovery, mediated by whole cells, exopolymeric substances (EPS) and biosurfactants of the indigenous and non-pathogenic Pseudomonas veronii 2E to be applied in the development of wastewater biotreatments. An electrochemical biosensor was developed using P. veronii 2E biosorption mechanism mediated by the cell surface associated to bound exopolymeric substances. A Carbon Paste Electrode modified with P. veronii 2E (CPEM) was built using mineral oil, pre-washed graphite power and 24 h-dried cells. For Cd(II) quantification the CPEM was immersed in Cd(II) (1-25 μM), detected by Square Wave Voltammetry. A similar procedure was used for 1-50 μM Cu(II). Regarding Cd(II), removal mediated by immobilized EPS was tested in a 50 ml bioreactor with 0.13 mM Cd(II), pH 7.5. A 54% metal retention by EPS was achieved after 7 h of continuous operation, while a 40% was removed by a control resin. In addition, surfactants produced by P. veronii 2E were studied for recovery of Cd(II) adsorbed on diatomite, obtaining a 36% desorption efficiency at pH 6.5. Cu(II) adsorption from a 1 mM solution was tested using P. veronii 2E purified soluble EPS in 50 mL- batch reactors (pH = 5.5, 32°C). An 80% of the initial Cu(II) was retained using 1.04 g immobilized EPS. Focusing on metal recovery, Cu nanoparticles (NPs) biosynthesis by P. veronii 2E was carried out in Cu(II)-PYG Broth at 25°C for 5 days. Extracellular CuNPs were characterized by UV-Vis spectral analysis while both extracellular and intracellular NPs were analyzed by SEM and TEM techniques. Responses of P. veronii 2E and its products as biosurfactants, bound and soluble EPS allowed Cu(II) and Cd(II) removal, recovery and biosensing resulting in a multiple and versatile tool for sustainable wastewater biotreatments.