Wood-derived adsorbents for the removal of pharmaceutical contamination from wastewater: a review

Bioremoval of non-steroidal anti-inflammatory drugs by Pseudoxanthomonas sp. DIN-3 isolated from biological activated carbon process

Ibuprofen (IBP) and diclofenac (DFC) are two of the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs) to treat inflammation and pain. However, they can impact the environment if not treated adequately before discharge into waterways. Biodegradation through the nitrification process is an alternative to reducing the concentration of these micropollutants (MPs) in wastewater. Thus, this work aimed to evaluate the effect of natural zeolite on IBP and DFC removal in a nitrifying batch reactor. Mini-reactors were set up with 90 mL of inoculum and 110 mL of synthetic wastewater with a concentration of 25 mg total ammonia nitrogen TAN/L, at 25 °C and 1 vvm (volume of air/volume liquid∙min) of aeration. Two conditions were tested: high concentrations (IBP = 700 μg/L, DFC = 100 μg/L) and low concentrations (IBP = 30 μg/L, DFC = 20 μg/L). The research used a concentration of 5 g/L of the natural zeolite. Results indicated that the zeolite negatively affected the nitrification rate. At high MPs concentration, the natural zeolite negatively affects the removal of IBP and DFC, where biodegradation and sorption are the mechanisms that eliminate both NSAIDs. Conversely, at low DFC and IBP concentrations, the natural zeolite improves the removal of IBP and DFC, wherein biodegradation is the primary removal mechanism.

Diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug, has been detected in effluents of conventional wastewater treatment plants worldwide. The presence of this compound in various water resources even at very low concentrations poses a big threat both to human health and aquatic ecosystems. In this study, the removal of diclofenac from aqueous solution using Fe-Mn binary oxide (FMBO) adsorbents was investigated. FMBO adsorbents were prepared at varying Fe/Mn molar ratios (1:0, 3:1, and 1:1) through simultaneous oxidation and co-precipitation methods. Batch adsorption experiments were conducted to evaluate the effects of important parameters, such as initial DCF concentration, FMBO dosage, solution pH, and Fe/Mn molar ratio, on DCF removal. Acidic to neutral pH conditions were more favorable for DCF adsorption, while increasing initial DCF concentration and adsorbent dosage resulted in higher DCF removal efficiencies for the three oxides. Lower Fe/Mn molar ratio during FBMO synthesis favored higher DCF removals of up to 99% within a wide pH range. Optimization of operating parameters (initial DCF concentration, FMBO dosage, and solution pH) by Box-Behnken design resulted in up to 28.84 mg g-1 DCF removal for 3:1 FMBO. Freundlich isotherm best described the experimental data, indicating that adsorption occurred on heterogeneous adsorbent surface. Chemisorption was the rate-limiting step of the DCF removal, as best described by the pseudo-second-order kinetic model.

MOF-808 and its hollow fibre adsorbents for efficient diclofenac removal

The emerging contaminants (ECs) are organic compounds including pharmaceuticals. These products are consumed in large quantities, favoring their continuous entrance to the environment and affecting the health of living beings. Diclofenac is a non-steroidal anti-inflammatory drug with analgesic properties of prolonged release. It is the commonest postoperative analgesic, and it is highly consumed without prescription. In recent years, the capability of microalgae to remove pharmaceuticals in water has been tested as a promising tool. In this work, the removal efficiency of diclofenac (16 µg/mL) by the microalga Nannochloropsis oculata CCAP 186/7 was evaluated. The major nutrient concentrations in Bold’s Basal Medium were modified (nitrogen and carbon: 50 and 100% of their original concentration) to know their effect in the removal of diclofenac. Drug degradation by light was also evaluated. The maximum removal capacity of diclofenac in the medium was 68.8%. The percentage of diclofenac adsorbed on the cell wall was between 6 and 12.7%. Around 23.6% of diclofenac was degraded by light after 18 days. N. oculata did not show growth inhibition due to the presence of diclofenac. The results obtained point to the promissory application of N. oculata as a bioremediation system for diclofenac removal.

Comprehensive review of wood-based composites as microwave absorbers: Utilizing wood-derived materials such as carbon, metal/metal oxides, and polymer composites as fillers

One of the contemporary problems is the widespread use of medicaments, which leads to an increased occurrence of these substances in the environment. The efficiency of conventional treatment processes for removing drugs from water is in most cases very little, if not zero. Treatment processes for removal of drugs include adsorption on activated carbon, membrane processes, and advanced oxidation processes. Within a specific university research project, a laboratory test was performed at the Institute of Municipal Water Management of the Faculty of Civil Engineering, Brno University of Technology, to monitor the effectiveness of diclofenac removal by selected sorption materials. Diclofenac was chosen for this experiment as a representative of one of the most widespread groups of drugs - non-steroidal anti-inflammatory drugs. The removal of diclofenac from water was performed using columns filled with sorption materials Filtrasorb F100, GEH and Bayoxide E33. The aim of the test was to compare the selected sorption materials in terms of their effectiveness in removing diclofenac from water. From analyses of water taken at predetermined time intervals after filtration through said materials, it was found that the most suitable material for removing diclofenac from water is Filtrasorb F100.

Non-steroidal anti-inflammatory drugs (NSAIDs) are currently considered a first-line treatment of renal colic. Their action has been ascribed to the inhibition of renal prostaglandin synthesis, which decreases renal blood flow and diuresis, and consequently lowers the pressure in the renal pelvis and ureter. However, the effects of NSAIDs on induced contractions of ureteral smooth muscle have received little attention. Also, there is a lack of clinically relevant spasmolytic drugs for the ureter. Therefore, we studied the influence of the non-selective cyclooxygenase (COX) inhibitor diclofenac, a NSAID drug customarily used in the treatment of renal colic, and of NS-398, a selective COX-2 inhibitor, on induced contractions of the pig ureter. Serotonin (0.1-30 microM), norepinephrine (0.1-30 microM) and neurokinin A (0.03-10 microM) induced reproducible concentration-dependent contractions, which were inhibited by diclofenac and NS-398 (10-300 microM) in a concentration-dependent manner. The sensitivity of neurokinin A-induced contractions to diclofenac was 3-4 times greater than that of the amines. Depending on the concentration, inhibition ranged between 25 and 96% of the initially induced contractile activity. In the presence of inhibitors, supramaximal concentrations of agonists were unable to trigger recuperation of the initially induced contractions. Prostaglandin F2alpha did not reverse the effect of diclofenac on agonist-induced contractions. Removal of diclofenac or NS-398 from the organ baths showed that the inhibition was totally reversible. Thus, the non-selective COX inhibitor diclofenac and the selective COX-2 inhibitor NS-398 are almost equipotent in reducing agonist-induced contractions in the isolated porcine ureter. Although the clinical relevance of this spasmolytic effect remains to be demonstrated, the data suggest that patients suffering from renal colic may benefit not only from the anti-diuretic and analgesic effects of diclofenac, but also from its potential spasmolytic properties. Moreover, selective COX-2 inhibitors may have clinical potential, as they may cause fewer side effects.

Diclofenac is one of the most common, commercially available, non-steroidal anti-inflammatory drugs (NSAIDs) in the world, with thousands of tons produced and consumed per year, which creates issues related to its presence in water bodies and the need for its removal from them. Diclofenac forms complexes with cations of each metal, which has inspired a study to check if the formation/precipitation of such complexes can be used for effective diclofenac removal from water solutions. It was found that iron salts, e.g., FeCl3, can be used to remove diclofenac from a water solution in the form a of precipitated complex, provided that a high excess of iron salt was used. It has been observed that the diclofenac initial concentration of 5 × 10−4 M, as a result of FeCl3 addition, after 48 h, decreased by two orders of magnitude. Salts of other metals were found less effective in reducing diclofenac concentration. The iron cation–diclofenac interaction was found to be specific, since the precipitation of other drugs by iron cations has not been observed. In order to quantitively analyze the diclofenac removal (precipitation) by iron and other metal cations, the HPLC/ESI-MS analyses were performed.

This study aims to demonstrate the feasibility of the use of chestnut waste as a green and circular material for developing iron-based photocatalysts for non-steroidal anti-inflammatory drug (NSAID) photodegradation. Four Fe-based catalysts and two pristine biochars were obtained upon a pyrolysis process at 500 and 700 °C and fully characterised. Due to the applied synthesis, iron is present in the form of isotropic grains of magnetite (Fe3O4), quite homogeneously dispersed onto the biochar. The textural properties of all the materials are mainly determined by the pyrolytic temperature, which results in macroporous materials at 500 °C and microporous ones at 700 °C. Fe-based catalysts were tested in Diclofenac (DFC) photodegradation. DFC removal was the result of both adsorption and photocatalytic reactions. Despite the good yield in DFC removal (80–100%), the formation of degradation by-products can partially invalidate the good effectiveness of this approach. However, the encouraging results of this study represent a step forward for the possible development of waste-derived biochar-based catalysts for in-field application.

The presence of an ionized carboxyl group in the widely used non-steroidal anti-inflammatory (NSAID) drug diclofenac potassium results in a high mobility of diclofenac and in its low sorption under conditions of slow sand filtration or subsoil passage. No diclofenac degradation was detected in pure water or sludge during one month. Tertiary treatments of wastewater indicated that the effective removal of diclofenac was by reverse osmosis, but the removal by activated carbon was less satisfactory. This study presents an efficient method for the removal of diclofenac from water by micelle–clay composites that are positively charged, have a large surface area and include large hydrophobic domains. Adsorption of diclofenac in dispersion by charcoal and a composite micelle (otadecyltrimethylammonium [ODTMA] and clay [montmorillonite]) was investigated. Analysis by the Langmuir isotherm revealed that charcoal had a somewhat larger number of adsorption sites than the composite, but the latter had a significantly larger binding affinity for diclofenac. Filtration experiments on a solution containing 300 ppm diclofenac demonstrated poor removal by activated carbon, in contrast to very efficient removal by micelle–clay filters. In the latter case the weight of removed diclofenac exceeded half that of ODTMA in the filter. Filtration of diclofenac solutions at concentrations of 8 and 80 ppb yielded almost complete removal at flow rates of 30 and 60 mL min−1. One kilogram of ODTMA in the micelle–clay filter has been estimated to remove more than 99% of diclofenac from a solution of 100 ppb during passage of more than 100 m3.

Removal of non-steroidal anti-inflammatory drugs from water using high surface area nanographene: Kinetic and thermodynamic studies

Diclofenac (DCF), a non-steroidal anti-inflammatory drug (NSAID) and sulfamethoxazole (SMX), an antimicrobial agent, are in common use and can be often detected in the environment. The constructed wetland systems (CWs) are one of the technologies to remove them from the aquatic environment. The final effect of the treatment processes depends on many factors, including the interaction between plants and the plant-associated microorganisms present in the system. Bacteria living inside the plant as endophytes are exposed to secondary metabolites in the tissues. Therefore, they can possess the potential to degrade aromatic structures, including residues of pharmaceuticals. The endophytic strain MG7 identified as Microbacterium sp., obtained from root tissues of Phalaris arundinacea exposed to DCF and SMX was tested for the ability to remove 2 mg/l of SMX and DCF in monosubstrate cultures and in the presence of phenol as an additional carbon source. The MG7 strain was able to remove approximately 15% of DCF and 9% of SMX after 20 days of monosubstrate culture. However, a decrease in the optical density of the MG7 strain cultures was observed, caused by an insufficient carbon source for bacterial growth and proliferation. The adsorption of pharmaceuticals onto autoclaved cells was negligible, which confirmed that the tested strain was directly involved in the removal of DCF and SMX. In the presence of phenol as the additional carbon source, the MG7 strain was able to remove approximately 35% of DCF and 61% of SMX, while an increase in the optical density of the cultures was noted. The higher removal efficiency can be explained by adaptive mechanisms in microorganisms exposed to phenol (i.e. changes in the composition of membrane lipids) and by a co-metabolic mechanism, where non-growth substrates can be transformed by non-specific enzymes. The presence of both DCF and SMX and the influence of the supply frequency of CWs with the contaminated wastewater on the diversity of whole endophytic bacterial communities were demonstrated. The results of this study suggest the capability of the MG7 strain to degrade DCF and SMX. This finding deserves further investigations to improve wastewater treatment in CWs with the possible use of pharmaceuticals-degrading endophytes.

Hydroxylamine enhanced Cu(II)/peroxydisulfate system for diclofenac degradation: Efficiency, influence factors and mechanism

Characterization of the catabolic pathway of diclofenac in Raoultella sp. KDF8