Conventional photocatalysts suffer from inefficient charge separation and rapid recombination rate of the electron-hole pairs. The motivation of the present study is, hence, to develop a composite of CuO nanoparticles and O-doped-g-C3N4 (CN) to address the mentioned issues for the efficient removal of naphthalene (NAP), one of the most abundant polycyclic aromatic hydrocarbons (PAHs) in aquatic media. The nanoparticles were characterised by XRD, STEM, EDS, gas adsorption (BET isotherm), XPS, FTIR and band gap analysis. Mott-Schottky studies were performed to understand the formation of the heterojunction in the O-doped-g-C3N4-CuO (OGC) photocatalyst. The prepared n-p-type heterostructure nanocomposite with a tuned band gap energy (1.55 eV, compared to 2.49 eV for CN and 1.79 for CuO) offered efficient removal of NAP by promoting the generation and separation of electron-hole pairs. The optimisation indicated the best performance (87.1 % of 20 mg of NAP) of the system using OGC (0.25 g/L) at pH 6 under visible light irradiation in 60 min. The removal rate of NAP was studied by pseudo-first-order reaction rate kinetics in addition to mechanistic studies on the NAP degradation pathways using quenching tests, electron paramagnetic resonance (EPR) measurements, and gas chromatography-mass spectrometry (GC-MS). According to the results achieved, OGC is an efficient heterojunction for the degradation of NAP under visible light irradiation by producing both center dot O2- and center dot OH radicals. Such an efficient process can significantly aid in enhancing the quality of the polluted waters and protection of the environment.

This study explores to optimize the synthesis of multi-walled carbon nanotubes (MWCNTs) from the carbonaceous low-cost resources (biochar and graphite) as the precursors under controlled microwave irradiation (MI) via a sustainable route and cost-effective route. Biochar used in this study was produced from the pyrolysis of pinewood that was characterized by high carbon content (similar to 72 %). Ferrocene was the catalyst to facilitate nucleation and growth of carbon nanotubes (CNTs) by providing catalytic sites for decomposing hydrocarbon precursors and subsequent formation of CNTs. While biochar alone as a precursor resulted in incomplete conversion of carbon atoms to CNTs, a mixture of biochar and graphite significantly improved the yield and quality of the final products. To enhance the properties of MWCNTs, variables such as microwave power, reaction time, operating temperature, and headspace capacity of the reactor were studied and optimized. Additionally, Response Surface Methodology (RSM) and Central Composite Design (CCD) were implemented to optimize specific surface area (SSA) and yield of the produced MWCNTs. Optimal conditions were determined at 9.70 min, the output power of 300 W, 80 degrees C, and a headspace of 10 %. Detailed characterization of the produced MWCNTs under optimum conditions revealed successful production of MWCNTs with diameters ranging from 12 nm to 46 nm with a wall thickness ranging from 2 nm and 6 nm. The materials developed represent a relatively high specific surface area of 229 m(2)/g. The study discussed the mechanisms involved in catalytic synthesis of MWCNTs from the carbonaceous resources.

Low sintering temperatures are essential for the sustainable development of ceramics and ceramic-based composites with the Cold Sintering Process (CSP) emerging as a promising technique. However, the formation of secondary phases, densification issues and functional behaviour may hinder its full potential. Here, we introduce a novel approach to the fabrication of dielectric composite thick films by combining CSP with a solvent-free polymer fibrillation process using polytetrafluoroethylene (PTFE). As proof of concept, we demonstrate a multilayer ceramic capacitor (MLCC) prototype based on BaTiO3-PTFE (similar to 3 wt%) fibrillated composite films with Ag screen-printed electrodes, processed omitting burnout step by CSP at 250 degrees C using Ba(OH)(2)8H(2)O as the transient phase. The resulting electrical performance of the MLCC prototype exhibits temperature stability, satisfying X8R capacitor grade requirements, and reduced dielectric losses. Additionally, a parallel-plate tunable capacitor is also designed using Ba1-xSrxTiO3-PTFE fibrillated thick films on copper foil, co-fired in a single step by CSP under the same conditions. Overall, these findings highlight the potential of CSP in bridging the gap between processing temperatures and the integration of polymers, metals and ceramics.

In this study, CuO nanoparticles were synthesised by chemical precipitation assisted by ultrasonic irradiation (UI), a rapid and environmentally friendly procedure without high temperature that enhances the sustainability of the synthesis process. They were also employed as a catalyst to activate peroxydisulfate (PDS) in the removal of ciprofloxacin (CIP) from a polluted solution. The effects of various factors, such as CIP concentration, catalyst dosage, PDS concentration, and initial pH, on the efficiency of this contaminant treatment were investigated. Under optimal conditions, CIP and TOC removal reached 100% and 49%, respectively, after only 30 min of reaction time and using high initial concentrations of CIP (20 mg/L), PDS (0.5 mM), and CuO (0.5 g/L) in pH (10). For the best set of processing conditions, pseudo-first-order reaction rate kinetics can be assumed and characterised. The possible degradation pathway of CIP is also suggested. Furthermore, by quenching experiment, the presence of O2−*, *OH, and SO4−* were identified, with O2−* being a radical species with great impact on CIP removal. This study demonstrates that, in alkaline environments, ultrasonically synthesised CuO can effectively activate PDS for the degradation of CIP, achieving total removal within 30 min. The results indicate that UI-synthesised CuO is a very promising catalyst for the removal of emerging organic pollutants.

Ba1-xSrxTiO3 compounds are widely recognized as leading dielectric materials for tunable electronic applications. To expand their applicability and enable integration with polymers and metals, there is a need for low-temperature processing. Here we show that Cold Sintering Process (CSP) enables the fabrication of Ba0.6Sr0.4TiO3 (BST) tunable dielectric ceramics, using Ba(OH)(2)8 H2O as a flux, at a temperature as low as 350 degrees C. A dielectric permittivity with a low magnitude of similar to 340 at 10 kHz, an electric-field tunability of 11%, and a thermal stability of +/- 7.1% over the temperature range of -90 degrees C to 85 degrees C are obtained for CSP BST that thus outperforms conventionally sintered BST ceramics. Significant decrease in the sintering temperature and enhanced dielectric performance respond to the current sustainability concerns related to energy efficiency and tunable device requirements.

The present research aimed to improve the efficiency of a novel walnut shell biochar-CuFe2O4/Fe2O3/CuO (BC-CuFeO) nanocomposite for the activation of peroxymonosulfate (PMS) for the degradation of carbamazepine (CBZ), as a recalcitrant organic pollutant. Ascorbic acid (H2A) and L-cysteine (LC) were utilized to significantly increase CBZ removal efficiency in the BC-CuFeO/PMS system. An L-16 Taguchi design was applied to identify the relative significance of the operating parameters for the degradation of CBZ. In addition, both the BC-CuFeO/PMS/H2A and BC-CuFeO/PMS/LC systems demonstrated outstanding CBZ degradation performance in the presence of humic acid, sodium chloride, and sodium nitrate, respectively. The scavenging experiments indicated that 1O2, ·OH, O2•−, and SO4•− were responsible for CBZ degradation in the BC-CuFeO/PMS/H2A system, while O2•−, 1O2, and ·OH contributed to CBZ degradation in the BC-CuFeO/PMS/LC system. Furthermore, the intermediates and pathways of CBZ degradation were determined via Q-TOF-MS analysis, and the potential toxicity of the products was assessed via Toxicity Estimation Software Tool analysis. The practicality of the nanocomposites was also evaluated through the fabrication of catalytic balls and catalytic membranes, followed by the study of their stability for wastewater treatment. In conclusion, this study provides novel and promising PMS activation methods for the efficient removal of recalcitrant pollutants from wastewater.

Fe and N co-doped walnut shell biochar (Fe,N-BC) was prepared through a one-pot pyrolysis procedure by using walnut shells as feedstocks, melamine as the N source, and iron (III) chloride as the Fe source. Moreover, pristine biochar (BC), nitrogen-doped biochar (N-BC), and alpha-Fe2O3-BC 2 O 3-BC were synthesized as controls. All the prepared materials were characterized by different techniques and were used for the activation of peroxymonosulfate (PMS) for the degradation of sulfamethoxazole (SMX). A very high degradation rate for SMX (10 mg/L) was achieved with Fe,N-BC/PMS (0.5 min(-1)), which was higher than those for BC/PMS (0.026 min(-1)), N-BC/PMS (0.038 min(-1)), and alpha-Fe2O3-BC/PMS 2 O 3-BC/PMS (0.33 min(-1)) under the same conditions. This is mainly due to the formation of Fe3C 3 C and iron oxides, which are very reactive for the activation of PMS. In the next step, Fe,N-BC was employed for the formation of a composite membrane structure by a liquid-induced phase inversion process. The synthesized ultrafiltration membrane not only exhibited high separation performance for humic acid sodium salt (HA, 98%) but also exhibited improved self-cleaning properties when applied for rhodamine B (RhB) filtration combined with a PMS solution cleaning procedure. Scavenging experiments revealed that 1 O 2 was the predominant species responsible for the degradation of SMX. The transformation products of SMX and possible degradation pathways were also identified. Furthermore, the toxicity assessment revealed that the overall toxicity of the intermediate was lower than that of SMX.

Ba(1-x)SrxTiO3 (BST) is a crucial dielectric material in tunable devices for modern wireless communication technologies, owing to high dielectric tunability and low dielectric loss. However, the conventional processing of BST ceramics requires a high sintering temperature of about 1350 degrees C. In this work, we demonstrate the feasibility of using Flash sintering (FS) and corresponding maps to process Ba0.6Sr0.4TiO3 ceramics, resulting in a 350 degrees C decrease in sintering temperature and 7 h reduction in sintering process time. The Flash-sintered BST exhibits a finer grain microstructure, lower dielectric loss, and significantly higher K-factor (figure of merit for tunability) when compared to conventionally sintered BST, unequivocally meeting the application criteria for tunable materials. Our findings highlight the effectiveness of FS as an alternative method for the rapid sintering of BST, while also opening up possibilities for further research into more efficient sintering processes for electroceramics.

The present research aimed to improve the efficiency of a novel walnut shell biochar-CuFe2O4/Fe2O3/CuO (BC-CuFeO) nanocomposite for the activation of peroxymonosulfate (PMS) for the degradation of carbamazepine (CBZ), as a recalcitrant organic pollutant. Ascorbic acid (H(2)A) and L-cysteine (LC) were utilized to significantly increase CBZ removal efficiency in the BC-CuFeO/PMS system. An L-16 Taguchi design was applied to identify the relative significance of the operating parameters for the degradation of CBZ. In addition, both the BC-CuFeO/PMS/H2A and BC-CuFeO/PMS/LC systems demonstrated outstanding CBZ degradation performance in the presence of humic acid, sodium chloride, and sodium nitrate, respectively. The scavenging experiments indicated that O-1(2), center dot OH, O-2(center dot-), and SO4 center dot- were responsible for CBZ degradation in the BC-CuFeO/PMS/H(2)A system, while O-2(center dot-), O-1(2), and center dot OH contributed to CBZ degradation in the BC-CuFeO/PMS/LC system. Furthermore, the intermediates and pathways of CBZ degradation were determined via Q-TOF-MS analysis, and the potential toxicity of the products was assessed via Toxicity Estimation Software Tool analysis. The practicality of the nanocomposites was also evaluated through the fabrication of catalytic balls and catalytic membranes, followed by the study of their stability for wastewater treatment. In conclusion, this study provides novel and promising PMS activation methods for the efficient removal of recalcitrant pollutants from wastewater.

Peracetic acid (PAA)-based advanced oxidation processes (AOPs) are promising technologies for the efficient treatment of persistent contaminants in wastewater. In this study, three different magnetic biochar (BC)-ferrospinel AFe(2)O(4) (A = Cu, Co, or Mn) nanocomposites were synthesized through a combined sol - gel/pyrolysis process for the activation of PAA to degrade carbamazepine (CBZ). The following order of efficiency was observed for CBZ degradation in the presence of PAA: BC-CoFe2O4 (100 %) > BC-MnFe2O4 (7 %) approximate to BC-CuFe2O4 (7 %). In addition, 0.8 mM PAA, 0.3 g/L catalyst, nearly neutral pH, and 333 K were identified as the optimal operating parameters for the degradation of 1 mg/L CBZ in the BC-CoFe2O4/PAA system. Mechanistic studies revealed that CH 3 C(O)OO center dot radicals are the dominant active species for the degradation of CBZ in the BCCoFe2O4 /PAA system, and the continuous conversion of Co(II) to Co(III) in this system is responsible for the generation of these radicals. In addition, the water matrices (e.g., humic acid (20 mg/L), NaCl (0.05 M), and NaNO 3 (0.01 M)) played negligible roles in the degradation of CBZ in the BC-CoFe2O4/PAA system. This system exhibited highly selective and reactive degradation of organic pollutants with electron -rich groups (e.g., CBZ (0.36 min(-1) ), sulfamethoxazole (0.12 min(-1)), and diclofenac (0.28 min(-1))). Furthermore, the degradation products of CBZ were identified, and possible degradation pathways and toxicity of these transformation products were proposed. The BC-CoFe2O4/PAA system demonstrated outstanding degradation performance in dynamic systems and real wastewater treatment applications. This study describes the performance of an efficient and easy -to -separate catalyst for the activation of PAA. This study facilitates the development and application of PAA-based AOPs for wastewater treatment.

The release of pharmaceutically active compounds (PhACs) into water bodies is among the current concerns of the scientific community considering the associated environmental and health factors, such as the toxic effects on aquatic microorganisms as well as the generation of antibiotic-resistant bacteria (ARBs) and antibiotic resistance genes (ARGs). Hence, there has been a trend to develop efficient and low-cost techniques to address this issue. This chapter aims to discuss the applicability of constructed wetlands (CWs) for the removal of PhACs. The mechanisms involved and the effects of various operating parameters on the performance of CWs have also been discussed, and the possibility for the optimization of the performance of such systems has been explored.

There has been an increasing rate in the release of pharmaceutically active compounds (PhACs) used to cure humans and animals into water bodies, causing various environmental and health issues. Among several methods developed for the removal of these compounds, adsorption has received particular attention due to its efficiency, cost-effectiveness, and ease of implementation. This chapter aims to discuss the main mechanisms involved in the adsorption of PhACs while examining the latest observations in the literature regarding the selection of sustainable materials for the efficient adsorption and removal of these compounds from polluted (waste)waters. As a point of high importance, the reusability of the adsorbents after being used for these processes is also discussed, and recommendations for future studies are presented. The chapter ends with further reading suggestions to support the discussions provided in the present chapter.

The presence of pharmaceutically active compounds (PhACs) in wastewaters originating from industrial and nonindustrial points can cause severe environmental issues, such as toxicity to aquatic organisms, even at relatively low concentrations. By affecting the performance of the primary producers, the overall function of the ecosystem can also be significantly interrupted. They can also result in the generation of antibiotic-resistant bacteria (ARBs) and antibacterial resistance genes (ARGs) in the receiving environment. The activated sludge (AS) process is the most common method for the treatment of municipal and industrial effluents. Hence, it would be vital to investigate the performance of such systems to control the release of PhACs into the environment. To this end, this chapter explores the fate and biodegradability of PhACs and the mechanisms involved in the removal of such compounds using AS methods. Recommendations have also been provided to promote such technologies for the elimination of such contaminants of emerging concerns.

Advanced oxidation processes (AOPs) have been considered in recent decades as efficient techniques for the efficient removal of recalcitrant and nonbiodegradable organic compounds from polluted (waste)waters. The basis of these methods is the generation of powerful oxidation agents in the medium to attack the target pollutants. Such methods can be divided into homogenous and heterogeneous AOPs. This chapter aims to explore the applicability of homogeneous AOPs (HO-AOPs), including both energy-free and energy-intensive HO-AOPs, for the elimination of pharmaceutically active compounds (PhACs) from the containing streams. The involved mechanisms as well as the outlook for future studies have also been discussed to promote the application of such technologies for the efficient removal of PhACs.

A major challenge for integration of functional oxides, such as ferroelectrics, into microelectronics and flexible electronics is the reduction of their processing temperature, which needs to be lower than the degradation temperature of silicon and flexible plastic substrates. Aiming that, attention has been given to low-temperature processing of oxide films by chemical solution deposition (CSD). In the field of ferroelectrics, potassium sodium niobate ((K1-xNax)NbO3, KNN) has aroused a special interest due to its eco-friendliness, despite the high crystallization temperature. In this work, polycrystalline KNN thin films have been fabricated for the first time at a temperature as low as 400 degrees C using a modified CSD process, the Seeded Photosensitive Precursor Method (SPPM). Despite this low processing temperature, monophasic and stoichiometric films with appreciable values of remnant polarization, P-r similar to 10.8 mu C/cm(2), and hysteretic piezoresponse are obtained. These results open a window to the direct integration of KNN films into the high-performance electronic devices.

K0.5Na0.5NbO3 (KNN) is as a relevant lead-free piezoelectric material due to its piezoelectric performance and a high Curie temperature. Although high-sintering temperature is required for obtaining dense KNN ceramics, it favours alkalis volatilization with deleterious effects on the physical properties. Together with the need of more environmentally-friendly technologies for ceramic manufacturing, cold sintering (CSP), a low temperature sintering process, is a promising technique. CSP of incongruently dissolving materials (with different dissolution rates of constituents) is, however, a challenge. In this work, a systematic study of the interaction of KNN particles with water under different pH conditions and temperatures is used to elucidate the nature and mechanisms of KNN dissolution. The KNN dissolution follows the trend [K+] > [Na+] >> [Nb5+]. Differences are demonstrated between acidic, neutral, and alkaline conditions, with the latter exhibiting less incongruence. Acidic pH increases solubility of KNN and promotes the incongruence of dissolution. Oppositely, alkaline pH decreases solubility of KNN and prevents dissolution incongruence. The incongruence of KNN dissolution in aqueous media is quantified. These observations have implications for our understanding of powders dissolution and offer opportunities to control the stoichiometry of the powders, that might be the key for CSP of incongruently dissolving materials.

Extraction of the energy from chemical compounds present in the content of the wastewaters has been considered an interesting idea to address issues such as the scarcity of clean water resources and the ongoing need for renewable energies. In this regard, microbial fuel cells (MFCs) have been rapidly developed in recent years to generate electrical energy from organic and inorganic pollutants by the activity of specific microbial strains. There are reports of the applicability of this technology to deal with a wide range of organic compounds. However, the presence of some specific compounds can interrupt the performance and failure of such systems. This chapter has aimed to explore the potential of MFCs for the treatment of effluents containing pharmaceutically active compounds (PhACs) and the possible effects of such compounds on the microbial communities in MFCs. The opportunities for further improvements of such systems and the research hotspot have also been discussed, and recommendations have been provided for future studies to push commercialization of such technologies.

The degradation kinetics and mechanisms of various types of recalcitrant organic pollutants (ROPs) by a novel biochar-CuO (B-CuO)/periodate (PI) system have been deeply investigated in the present study. More precisely, the study aimed to explore the significant effects of pH on the formation of various oxidative species using this treatment system. According to the results achieved, iodate (IO3 center dot) and periodate radicals (IO4 center dot), center dot OH and O(3P) were mostly generated at pH approximate to 7, resulting in the efficient removal of methylene blue (MB) (90% after 30 min, kobs = 0.09 min-1), while the system favoured the formation of O(3P) under highly alkaline pH values (pH = 11), leading to lower degradation kinetics of the pollutant (51% after 30 min, kobs = 0.028 min-1). Additionally, no oxidative species were found at highly acidic pH values (pH = 3), and no significant MB removal was observed (21% after 30 min, kobs = 0.0081 min-1). Elevating the temperature (from 25 degrees C to 80 degrees C) and bubbling with nitrogen or oxygen gas also did not have any significant effects on the degradation of ROPs. Additionally, the system maintained its efficiency in various water matrices, including real wastewater, confirming the applicability of the biochar-CuO/PI system for real water treatment processes. The system also exhibited a high degradation efficiency for other types of ROPs, such as ciprofloxacin. Experiments using ultra-high performance liquid chromatography in combination with quadrupole time-of-flight mass spectrometry were performed to identify the degradation products and pathways of MB, revealing the contribution of two different degradation pathways and the formation of five degradation products in the B-CuO/PI system. The ECOSAR program was employed to evaluate the predicted toxicity of the degradation products. The results showed that the system could efficiently detoxify MB.

Pharmaceutically active compounds (PhACs) have been increasingly used to cure health issues in humans and animals. This has led to the release of large amounts of these compounds, creating environmental and health concerns. To control their concentrations in the environment, there have been efforts among the scientific community to develop analytical methods to detect and quantify such compounds and their possible transformation products. Such methods have been efficiently used for exploring the effectiveness of (waste)water treatment technologies that have been developed rapidly in recent years to remove PhACs from the source, preventing their release into the environment. This chapter has aimed to introduce such techniques for the detection of various pharmaceutically active compounds, their quantification, and those methods that can be used to identify the mechanisms involved in the removal of PhACs using various physico-chemical and biological treatment systems.

Membrane filtration has been considered a popular method for the treatment of (waste)waters originating from various industrial and nonindustrial sources. They have also been recently used for the removal of PhACs as an emerging environmental concern. This chapter aims to provide an overview of various membrane filtration techniques (i.e., forward osmosis and reverse osmosis, nanofiltration, ultrafiltration, microfiltration, and membrane bioreactors) that have been implemented for the removal of such compounds from polluted (waste)waters. The existing challenges (i.e., fouling) for the application of such technologies and the opportunities for further studies have been briefly reviewed and discussed.