Fast Removal Research Articles

Precursor-oriented design of nano-alumina for efficient removal of antibiotics

Rapid and efficient removal of environmental antibiotics is vital to curb bacterial resistance. Through rational precursors-oriented design, we attain the best Al2O3 absorbent by 500 °C calcination of ammonium aluminium carbonate hydroxide (AACH) precursor from NH4HCO3 route (AACH-NH4HCO3-500) for fast and efficient removal of tetracycline (TC) and other antibiotics from environmental waters including high-salinity wastewater. AACH-NH4HCO3-500 (0.25 g·L−1) can remove (69.92 ± 1.78)% of aqueous TC (0.025 g·L−1) within 5 min and (97.62 ± 2.75)% within 2 h, and the adsorption capacity is 444.4 mg·g−1, which is the highest qmax of TC for the 2 h-adsorptions among numerous adsorbents. AACH-NH4HCO3-500 has fine tolerance to the coexisting substances, and can be easily regenerated and reused, and has no harm even discarded. The relations among the synthetic methods, the structural features, and the adsorption functions of Al2O3 are disclosed through a systematic comparison of the commercial Al2O3 and different Al2O3 nanomaterials attained from three precursors produced by five different routes. The reasons behind the exceptional adsorption performance are discussed throughout. Our findings would facilitate the development of excellent adsorbents for removal of other pollutants.

Synthesis and optimization of alkaline earth borate glasses doped with Fe2O3: Significance of BaO/MgO on the physical, structural features and radiation shielding performance

In this study, MgO–BaO–B2O3–Fe2O3 glasses were synthesized using the conventional melt and quench method, and the role of BaO and MgO in dictating their structural, physical, and optical properties was investigated. The fast neutrons, electrons, and heavy charged radiation transmission abilities of the glasses were delineated with the aim of evaluating their capacity to act as radiation insulators. The density of the glasses decreased from 3.40 g/cm3 to 2.89 g/cm3 as the MgO content increased. Also, the obtained optical bandgap increased from 1.90 eV to 2.20 eV with the increase of MgO in the MBBFe glasses. The stopping powers of electrons vary from 1.39 to 11.01 MeVcm2/g, 1.41–11.37 MeVcm2/g, 1.43–11.69 MeVcm2/g, 1.44–11.87 MeVcm2/g and 1.46–12.05 MeVcm2/g for glasses with MgO contents of 0 (MBBFe0), 5 (MBBFe1), 10 (MBBFe2), 12.5 (MBBFe3), and 15 (MBBFe4) mol%, respectively. Generally, the increase in the MgO content of the glasses led to increased mass stopping powers of the protons, alpha particles, and carbon ions. The replacement of BaO with MgO compromised the thermal neutron interaction probabilities of the present glassy specimens. The MBBFe-0 glass had the best thermal neutron interaction cross sections. The fast neutron removal cross-section of the glasses was within the range of 0.1037–0.1070 cm−1 with MBBFe-3 having the highest value and MBBFe-4 the least. The increase in the BaO suppresses photon buildup within the glass system. The MBBFe-glasses displayed good physical and optical properties, photon and neutron shielding abilities, which makes them attractive for diverse shielding and optical functions.

Oxidation of organic pollutants over MnO2 in cold water assisted by peroxydisulfate

MnO2 can be used in advanced oxidation processes to activate peroxydisulfate (PS) and generate reactive species such as sulfate radicals (SO4•-), hydroxyl radicals (•OH) and singlet oxygen (1O2) for the abatement of organic water contaminants. Alternatively, one can use MnO2 as particulate oxidant which, in contrast to PS, is active already at low temperatures. This low-temperature activity is particularly attractive for in situ groundwater treatment. The roles of PS and MnO2 as oxidant and catalyst, respectively, may invert: MnO2 functions as primary oxidant and PS works as re-oxidant of reduced Mn-oxides. In this way, the limited oxidation capacity of particulate MnO2 can be overcome. So far, such reaction systems have not been extensively explored.In the present study, the degradation of 4-hydroxybenzoic acid (HBA) by PS + MnO2 was studied under various experimental conditions, by varying reaction temperature (15–45 °C), reagent concentrations, and water matrix. Both PS and MnO2 alone have the ability to effect the oxidation of HBA. In the co-presence of PS and MnO2, a fast removal of HBA from water was achieved even at low temperatures (half-life of HBA about 0.5 h with 2.4 g L-1 MnO2 at 25 °C), owing to a synergic effect between the two components.Quenching experiments indicate that the primary HBA oxidation step is a heterogeneous reaction on the MnO2 surface rather than a homogeneous reaction driven by SO4•- or 1O2, as frequently reported in literature. This is in line with results from the PS driven oxidation of perfluorooctanoic acid which is not significantly enhanced in the presence of MnO2.

Myrica esculenta Leaf Extract-Assisted Green Synthesis of Porous Magnetic Chitosan Composites for Fast Removal of Cd (II) from Water: Kinetics and Thermodynamics of Adsorption.

Heavy metal contamination in water resources is a major issue worldwide. Metals released into the environment endanger human health, owing to their persistence and absorption into the food chain. Cadmium is a highly toxic heavy metal, which causes severe health hazards in human beings as well as in animals. To overcome the issue, current research focused on cadmium ion removal from the polluted water by using porous magnetic chitosan composite produced from Kaphal (Myrica esculenta) leaves. The synthesized composite was characterized by BET, XRD, FT-IR, FE-SEM with EDX, and VSM to understand the structural, textural, surface functional, morphological-compositional, and magnetic properties, respectively, that contributed to the adsorption of Cd. The maximum Cd adsorption capacities observed for the Fe3O4 nanoparticles (MNPs) and porous magnetic chitosan (MCS) composite were 290 mg/g and 426 mg/g, respectively. Both the adsorption processes followed second-order kinetics. Batch adsorption studies were carried out to understand the optimum conditions for the fast adsorption process. Both the adsorbents could be regenerated for up to seven cycles without appreciable loss in adsorption capacity. The porous magnetic chitosan composite showed improved adsorption compared to MNPs. The mechanism for cadmium ion adsorption by MNPs and MCS has been postulated. Magnetic-modified chitosan-based composites that exhibit high adsorption efficiency, regeneration, and easy separation from a solution have broad development prospects in various industrial sewage and wastewater treatment fields.

Pb2+ ion removal from contaminated aqueous solution by adsorption onto Graphene Oxide Sand Composite (GOSC) for efficient water purification

Lead is a heavy metal which affects all the systems of human body. An easy method for removal of lead contamination was developed by using graphene oxide coated sand particle (GOSC). In this study, GOSC was prepared using sand particle and sucrose solution under controlled heating program which shows efficient adsorption behavior compared to other adsorbents. GOSC offered very fast removal of Pb+2 with small amount of GOSC (0.09g) in 100 ppm adsorbate solution. Characterization of GOSC was done by using several advanced techniques like FTIR, XRD, SEM, EDX, TEM, DSC, and Zeta Potential measurements before and after adsorption of lead ion (Pb2+). Adsorption shows superiority over other methods because it involves effective and high removal efficiency adsorption (above 90%). Various parameters like the effect of time, pH, adsorbent, dose effect, concentration and temperature were studied. Various adsorption and kinetic models were also investigated using adsorption data and results showed that removal of lead (Pb2+) ion follows Langmuir isotherm (R2 = 99%), second order kinetics (R2 = 98%) and higher intraparticle diffusion (R2= 98%). The high percentage removal of metal ions with little quantity of GOSC confirmed that GOSC is an excellent, effective and economic adsorbent.

Cooperative reinforcement of photocatalysis-coupled capacitive deionization in fructose intercalated MoS2 for removal of tetracycline

CDI technology have attracted attention as a promising next generation water remediation technology, while the sustainability and the removal capacity inhibit the application of CDI for organic pollutant removal. Herein, we introduced photocatalysis coupled with CDI technology for removal of tetracycline (TC) by using MoS2/C electrode as a bifunctional catalyst, which could achieve the self-cleaning of the working electrode through in-situ degrading the adsorbed TC. On account of the introduction of fructose, the restrained ultrathin MoS2/C nanosheets composite with enhanced ion storage capacity and promoted photo-generated electron-hole pairs separation efficiency was constructed. By using TC as a model molecule for mimicking organic contaminants, MoS2/C electrode in the photocatalysis-coupled CDI system exhibited a superior TC removal capacity of 1302.5 mg g−1, TC removal efficiency of 84.8 %, and fast removal kinetics. Moreover, it achieved six cycles through “self-cleaning” based on the cooperative effect of photocatalytic degradation and electrosorption. Finally, FT-IR and radical scavenger experiments were utilized to demonstrate the mechanism of TC degradation. This study paves a way of photoelectronic degradation of antibiotics through a synergetic effect of electrosorption and photocatalysis.

Tailoring a correlation between fracture resistance improvement, elastic moduli, mechanical and nuclear radiation shielding properties for sodium-borate glasses through Gallium(III) oxide incorporation

In the event of unanticipated events or emergency situations, such as equipment malfunctions or accidents, it is crucial for radiation shielding materials to preserve their structural integrity. Enhancing the fracture resistance of glasses has a wide range of benefits that extend to safety, durability, cost savings, energy efficiency, environmental considerations, technological innovation, consumer confidence, manufacturing efficiency, and reduced downtime. This research examines the characteristics of sodium-borate glasses with a nominal composition of 25Na2O-xGa2O3-(75-x)B2O3, (where x: 5, 10, 15, 20, 25, 27.5, and 30 mol%). The aim is to enhance fracture resistant qualities and radiation absorption with the addition of Ga2O3 into the glass composition. In addition to elastic moduli and mechanical properties, gamma-ray and fast neutron removal cross section values are determined for each glass sample. In addition to enhancing mechanical characteristics and elastic moduli, the use of Ga2O3 reinforcement has shown notable improvements in the gamma-ray and fast neutron absorption properties of sodium-borate glass samples. The NGB31.4 sample demonstrated the highest level of improvement in gamma-ray and neutron absorption characteristics. For example, the mass attenuation coefficients were calculated as 1.86645 cm2/g, 1.92189 cm2/g, 1.98875 cm2/g, 2.04052 cm2/g, 2.10506 cm2/g, 2.16271 cm2/g, and 2.17266 cm2/g for NGB5, NGB10, NGB15, NGB20, NGB25, NGB30.5, and NGB31.4 at 15 MeV photon energy, respectively. This enhancement was accomplished by incorporating Ga2O3 into the baseline sample at a mole percentage of 31.4 %. Hence, it can be concluded that the incorporation of Ga2O3 into sodium-borate glasses has the potential to serve as a systematic mechanism, leading to enhancements in mechanical strength and radiation absorption characteristics, thereby making these glasses more suitable for their intended applications. Among these samples, the greatest level of integration observed was 31.4 % mole Ga2O3. The lack of ability to examine the behavioral alterations resulting from higher Ga2O3 content in sodium-borate glasses may be regarded as a limitation of the present study. However, it is very advisable to do more research among the scientific community to thoroughly explore the potential impact of Ga2O3 on sodium-borate glasses.

Fe-nanoparticle effect on polypropylene for effective radiation protection: Simulation and theoretical study

An evaluation of the gamma-neutron shielding capabilities of polymer nanocomposite materials based on polypropylene and iron nanoparticles is presented in this study. The chemical composition of the materials is (100-x) PP-Fex, (where x = 0.1, 0.3, 0.5, 1, 2 and 5 wt percent). For the proposed polymer samples with photon energies ranging from 30 to 2000 KeV, the mass attenuation coefficient (MAC), a crucial parameter for studying gamma-ray shielding capability, was calculated using the Geant4 Monte Carlo code. Results were compared with those predicted by EpiXS. The values of the Geant4 code and the EpiXS software were both found to be in excellent agreement. Using the mass attenuation coefficient values, we determined the linear attenuation coefficients, electron density, effective atomic number, and half value layer for all the samples. The shielding properties of the polymer samples were also evaluated by estimating both the fast neutron removal cross-section and the mean free path of the fast neutron at energies between 0.25 and 5.5 keV. The study's findings indicate a positive correlation between the Fe nanoparticle content and the gamma-ray shielding performance of PP-Fe polymer samples. Out of the several glasses that were evaluated, it was found that the PP-Fe5 polymer sample demonstrates the highest efficacy in terms of gamma-ray shielding. Moreover, the polymer sample PP-Fe5, which consists of 5 mol% of iron (Fe), exhibits the highest value of ∑R (1.10650 cm-1) and the lowest value of the mean free path for fast neutrons. This indicates that the PP-Fe5 possesses better gamma-neutron shielding efficiency.

Adsorption of per- and polyfluoroalkyl substances (PFAS) from water with porous organic polymers

Per- and polyfluoroalkyl substances (PFAS) are man-made environmental contaminants causing increasing global concern due to their adverse effect on environmental and human health. Conventional treatment methods are ineffective in removing short-chain PFAS because they are persistent and recalcitrant to treatment. This study evaluated the performance of a structurally-tunable and chemically-stable porous organic polymer (POP) for PFAS removal under realistic environmental conditions. The POP demonstrated an exceptionally high removal efficiency (>95%) within 15 min when the initial PFAS concentration was approximately 400 ng/L. The adsorption of PFAS on the POP was not significantly affected by changes in solution pH within the range of 5–9. The common co-contaminants in water competed with short-chain PFAS for active sites during the adsorption process following the order of natural organic matter (NOM), long-chain PFAS, and Cl−. The Freundlich-type model could predict the multicomponent interactions well with a R2 value above 0.91. The spent POP was effectively regenerated using a mixture of the 10% NaCl and 30% methanol solution and the PFAS removal maintained at 90% through five adsorption and desorption cycles. The characteristics of the designed POP make it a highly promising and stable absorbent. It enables fast and effective removal of short-chain PFAS.

Warming modulates the photosynthetic performance of Thalassiosira pseudonana in response to UV radiation.

Diatoms form a major component of phytoplankton. These eukaryotic organisms are responsible for approximately 40% of primary productivity in the oceans and contribute significantly to the food web. Here, the influences of ultraviolet radiation (UVR) and ocean warming on diatom photosynthesis were investigated in Thalassiosira pseudonana. The organism was grown at two temperatures, namely, 18°C, the present surface water temperature in summer, and 24°C, an estimate of surface temperature in the year 2,100, under conditions of high photosynthetically active radiation (P, 400-700 nm) alone or in combination with UVR (P + UVR, 295-700 nm). It was found that the maximum photochemical yield of PSII (Fv/Fm) in T. pseudonana was significantly decreased by the radiation exposure with UVR at low temperature, while the rise of temperature alleviated the inhibition induced by UVR. The analysis of PSII subunits turnover showed that high temperature alone or worked synergistically with UVR provoking fast removal of PsbA protein (KPsbA), and also could maintain high PsbD pool in T. pseudonana cells. With the facilitation of PSII repair process, less non-photochemical quenching (NPQ) occurred at high temperature when cells were exposed to P or P + UVR. In addition, irrespective of radiation treatments, high temperature stimulated the induction of SOD activity, which partly contributed to the higher PSII repair rate constant (Krec) as compared to KPsbA. Our findings suggest that the rise in temperature could benefit the photosynthetic performance of T. pseudonana via modulation of its PSII repair cycle and protective capacity, affecting its abundance in phytoplankton in the future warming ocean.

Why the Perfectly Symmetric Cobalt‐Pentapyridyl Loses the H2 Production Challenge: Theoretical Insight into Reaction Mechanism and Reduction Free Energies

AbstractResearchers have extensively investigated photo‐catalytic water reduction utilizing Cobalt‐based catalysts with polypyridyl ligands. While catalysts exhibiting distorted polypyridyl ligand demonstrate higher H2 production yields, those with ideal octahedral coordination display poor performance. This outcome suggests the crucial role of ligand framework in catalytic activity, yet reasons behind the disparity in H2 production rates for catalysts with octahedral geometries remain unclear. We theoretically examined the water reduction mechanism of Co‐based poly‐pyridyl catalyst, CoPy5, having perfect octahedral coordination. We clarified the effect of octahedral coordination by utilizing each intermediate step of ECEC mechanism. We determined spin states, solvent response, electronic structures, and reduction free energies. CoPy5 with perfect octahedral coordination, alongside its distorted counterparts, exhibit similar spin states as the reaction progresses through each intermediate step. However, the first reduction free energy obtained for the CoPy5 is slightly higher than that of its distorted counterparts. Following the second protonation, resulting H2 molecule experiences limited diffusion from the Co center due to the compact structure of the CoPy5, which blocks the Co center for the next H2 production cycle. Catalysts having distorted octahedral geometries facilitate fast removal of H2 into the solvent. Thus, the reaction center becomes immediately available for subsequent H2 production.

An investigation of some ionizing radiation interaction parameters in selected composite scintillation materials

In this study, the interaction parameters of neutrons, charge particles and gamma rays in seven inorganic scintillation materials with densities ranged from 3.86 to 8.30 g/cm3 were theoretically examined. SRIM Monte Carlo software was used to determine the range of H + , H e + + , A u + and O − − ions in the energy range (0.01–20) MeV, Phy-X/PSD while Py-MLBUF computer programs were used to estimate gamma radiation interaction parameters in the energy range (0.02–15) MeV. The electron total stopping power and range values at energies ranging from 0.01 to 1000 MeV were calculated using the ESTAR NIST program. The fast neutron removal cross-section (FNRCS) and the macroscopic effective removal cross-section (MRCS) were calculated using the Phy-X/PSD and MRCS tools, respectively. The outcomes of this research showed that the range of H + , H e + + , A u + and O − − ions increased with decreasing sample density but decreased with increasing projectile energies; the largest range of H + is 2090 µm in the lowest density S1 sample, while the range of A u + is 5.16 µm in the same sample. The denser sample S7 had the highest stopping power and the lowest range at higher electron energies. The S1 sample had the highest calculated HVL value of 5.403 cm, while the S7 sample had the lowest calculated HVL value of 0.0008 cm. Rising sample density causes the MAC to rise, while rising gamma energy causes the MAC to decrease. The highest MAC value recorded was 107 cm2/g at 0.015 MeV in the S7 sample, and the lowest value recorded was 0.0369 cm2/g at 15 MeV in the S1 sample. For all inorganic scintillation samples at particular gamma energies, the standard deviations for the MAC, HVL and Zeff values between the Phy-X/PSD and, Py-MLBUF programs were calculated. With energy range variation, the results for Zeff for the two samples S2 and S4 appeared to be constant. Regards to the fast neutrons, the heights value’s of FNRCS, and MRCS were recorded for S7.

3D Wood Microfilter for Fast and Efficient Removal of Heavy Metal Ions from Water.

Adsorption is an effective method for the treatment of heavy metal ions in water; however, the existing adsorbents are complicated to prepare, and costly and difficult to recover. In this work, a 3D wood microfilter was prepared by modifying wood for the removal of heavy metal contaminants from water. First, a green deep eutectic solvent was used to remove lignin from beech wood. Then citric acid and l-cysteine were sequentially used to graft carboxyl and sulfhydryl groups (-SHs) on the surface of cellulose. Finally, a three-dimensional wood microfilter with an abundant porous structure and adsorption sites was formed. The adsorption kinetics and adsorption isotherms of heavy metal ions on the 3D wood microfilter were systematically investigated using Cu2+ and Cd2+ as model species. The results showed that the 3D wood microfilter had a fast adsorption rate and high saturation capacity for both Cu2+ and Cd2+. Based on the advantages of easy processing and multilayer assembly and stacking, a three-layer wood microfilter was designed to achieve high flux rate (1.53 × 103 L m-2 h-1) and high efficiency (>98%) for the removal of heavy metal ions in water. The enhancement mechanism of the adsorption process of Cu2+ and Cd2+ by the 3D wood microfilter was investigated using SEM and EDS, FTIR, and XPS characterization. The simple synthesis method and high adsorption efficiency of this wood microfilter provide a new strategy for the preparation of cheap, efficient, and recyclable adsorbents for heavy metal ions in water.

Tailoring stimuli-responsive PVDF-based copolymer membrane with engineered pore structure for efficient antibody purification

Membrane chromatography is considered as a sustainable alternative for downstream purification to overcome the production bottleneck of biopharmaceuticals. However, two of the major factors impeding its industrial adoption are the lack of controllable functionalization and competitive binding capacity. This work aimed to develop a one-pot synthesis strategy for fabricating a new class of pH-responsive poly(vinylidene fluoride)-graft-poly(dimethylaminoethyl methacrylate) (PVDF-g-PDMAEMA) membranes with anion exchangers, to achieve fast and accurate removal of albumin impurities from antibody streams. By utilizing a pre-functionalized copolymer with controlled ligand density, PVDF-g-PDMAEMA membranes with advantageous bicontinuous pore network structure were obtained via an unconventional nonsolvent thermally induced phase separation method. The membrane showed a competitive water permeance of > 6000 L m-2h−1 bar−1. Combining with dedicated static binding and isotherm studies, the membranes demonstrated distinct pH-responsive binding behaviour to model impurity bovine serum albumin (BSA) with maximal binding of 318.0 mg/g at pH 5.5. The dynamic flow-through binding experiments indicated that the membrane could effectively capture BSA from immunoglobulin G (IgG) (model antibody)/BSA mixed solution with a competitive binding capacity of 210.5 mg/g, producing IgG with purity > 90 % and nearly full recovery. Also, comprehensive analysis demonstrated the robustness of the membrane performance through five consecutive operation cycles, with or without harsh alkaline regeneration. The biocompatibility analysis further proved the membranes’ suitability in biopharmaceutical applications. This study provided a new route for designing future chromatographic membranes to promote its industrial uptake, pushing for energy-saving and effective downstream bioprocessing.

Impact of catalyst, chelating agent and light irradiation on electro-Fenton performance under not optimal conditions.

Electro-Fenton is a promising game-changer for distributed wastewater treatments for the removal of recalcitrant compounds that it is possible to find in industrial effluent and looking for a water reuse approach. This electrochemical advanced oxidation process (EAOPs) is able to provide fast removal of organic compounds, like dyes, due to the in-situ H2O2 production and its reaction with Fe2+ to form hydroxyl radicals. The literature clearly reports that this reaction reaches its optimum in acid conditions (pH = 3) and low catalyst concentrations [Fe2+<0.5 mM]. This paper wants to investigate the effects of the shifting from optimal conditions on the removal of reactive black 5 (RB5), treating solutions which contain a higher amount of catalyst and a less acid pH. Textile effluents usually contain also other metals able to act as catalyst for Fenton reaction, like copper. Here its activity has been investigated as well as the possible synergistic effect with Fe2+. The results confirm that copper can enhance RB5 removal, especially in those conditions critical for ferrous cation. In the second part, possible process modifications to overcome the issues introduced by unfavourable operating conditions (pH > 3 and Fe2+ > 0.5 mM) are considered, such as the usage of a chelating agent (EDTA) and the application of a light source. The results show the positive impact of these two system modifications highlighting the possibility to enlarge the application window of electro-Fenton systems.

Possible Uses of Decommissioned Coke Batteries

Since the 80s of the 20th century, as a result of the reduction in demand for coke, economic crises and the availability of coking coal, the operations of coke plants in Europe have been ending. Furthermore, the pressure for using renewable energy sources continues to increase, including the production of fuels. In most cases, the current solution is to add biocomponents to fuels produced in the classical way from oil. There are considerations about reusing these coke batteries, this time for the production of liquid fuels. Therefore, this work is devoted to the processing of biomaterials mixed with brown coal by the pyrolytic process. Extracted rapeseed meal, sunflower seed husks and dry distillery grain with solubles (DDGS) were selected as biomaterials. They are waste material from various productions, but these materials also show good energy potential. The brown coal came from the ČSA quarry, which is characterized by a low content of sulfur and ash and also improves the properties of liquid pyrolysis products, because it reduces polarity of organic phase, which enables easier separation of the aqueous and liquid phases of the product. Pyrolysis experiments were carried out in two different pyrolysis devices - i) in a micropyrolysis unit (sample loading: in the order of mg, heating rate: 100 °C s-1, fast removal of pyrolysis products); ii) in the pilot unit (sample weight: approx. 10 kg, heating rate: 5.2 °C min-1 and slower removal of pyrolysis products, cuboid shape of the pyrolysis retort simulating a coke oven battery). On the basis of mass balances and characteristics of micropyrolysis products, the pyrolysis temperature for pilot experiments was set at 650 °C. Behind the pyrolysis retort of the pilot unit, a thermic-catalytic reactor (catalyst: sulfurized aluminosilicate based on Ni-W) was connected in order to improve the quality of volatile pyrolysis products. The highest yields of organic phases of liquid products came from co-pyrolysis of coal and DDGS and coal with rapeseed meal. However, the characteristics of organic phases determined as the most advantageous material for the pyrolytic processing the rapeseed meal (specifically a higher proportion of aliphatic and aromatic hydrocarbons, a lower proportion of hydrocarbons with heteroatoms and a higher proportion of light fractions). The most beneficial pyrolysis mixture contained 35 % of rapeseed meal and the temperature in the catalytic part of the thermic-catalytic reactor was 300 °C.

Transition Metal Borides for All-in-One Radiation Shielding.

All-in-one radiation shielding is an emerging concept in developing new-generation radiation protection materials since various forms of ionizing radiation, such as neutrons and gamma rays, can occur simultaneously. In this study, we examine the ability of transition metal borides to attenuate both photon and particle radiation. Specifically, fourteen different transition metal borides (including inner transition metal borides) are selected for examination based on their thermodynamic stabilities, molecular weights, and neutron capture cross-sections of the elements they contain. Radiation shielding characteristics of the transition metal borides are computationally investigated using Phy-X/PSD, EpiXS and NGCal software. The gamma-ray shielding capabilities of the transition metal borides are evaluated in terms of the mass attenuation coefficient (μm), the linear attenuation coefficient (µ), the effective atomic number (Zeff), the half-value layer (HVL), the tenth-value layer (TVL), and the mean free path (MFP). The mass and linear attenuation factors are identified for thermal and fast neutrons at energies of 0.025 eV and 4 MeV, respectively. Moreover, the fast neutron removal cross-sections (∑R) of the transition metal borides are calculated to assess their neutron shielding abilities. The results revealed that borides of transition metals with a high atomic number, such as Re, W, and Ta, possess outstanding gamma shielding performance. At 4 MeV photon energy, the half-value layers of ReB2 and WB2 compounds were found as 1.38 cm and 1.43 cm, respectively. Most notably, these HVL values are lower than the HVL value of toxic Pb (1.45 cm at 4 MeV), which is one of the conventional radiation shielding materials. On the other hand, SmB6 and DyB6 demonstrated exceptional neutron attenuation for thermal and fast neutrons due to the high neutron capture cross-sections of Sm, Dy, and B. The outcomes of this study reveal that transition metal borides can be suitable candidates for shielding against mixed neutron and gamma radiation.

A sustainable and fast methodology based on magnetic activated carbon for removal of imidacloprid from aqueous solution

The occurrence of neonicotinoid insecticides in environmental waters represents a potential risk for the ecosystems and human health. Herein, an efficient procedure based on an activated carbon/magnetite (AC/Fe3O4) mixture adsorbent is proposed for fast removal of imidacloprid (IMI) as target molecule. The effects of contact time, adsorbent dosage and presence of inorganic salts on the adsorption characteristics of IMI on AC/Fe3O4 were evaluated by using a simple flow-system. Under optimal conditions, IMI was satisfactorily removed in only 10 min using AC/Fe3O4 (90:10 mass:mass ratio) at pH 7.0. The adsorption capacity was 192 mg g−1 at 25 °C. IMI only adsorbed on AC, but Fe3O4 was necessary to impart magnetic properties to AC. A comparative analysis of adsorption isotherms of several carbon-based adsorbents for IMI demonstrates that not only the maximum adsorption capacity of the adsorbent but also the affinity of the surface for the insecticide (given by the adsorption constant) needs to be considered when choosing an adsorbent. Materials with high maximum adsorption capacities are good for concentrated solutions, such as wastewaters; materials with high adsorption constants are especially good for more dilute solutions, such as environmental samples. Desorption of IMI was also tested under different pH conditions and effective desorption was achieved at pH 11.5 (25 °C), allowing the reuse of the material for subsequent adsorption runs without losing its capacity. Thus, an efficient, sustainable and low-cost adsorption procedure is proposed for fast removal of IMI from aqueous solution. These results demonstrate the potential applications of the studied mixture as adsorbent for developing alternative water cleaning technologies and analytical systems.

Reusing spent fluid catalytic cracking catalyst as an adsorbent in wastewater treatment applications

Spent fluid catalytic cracking (FCC) catalyst is a waste from oil industry generated in very high amounts globally, being a major environmental burden as it is mostly landfilled. The direct use of this waste in wastewater treatment applications is rare, and the present study aims to fill the existing research gap. This is the first systematic investigation regarding the use of spent FCC catalyst as adsorbent material, for extracting methylene blue (MB) (pollutant model molecule) from wastewater.The effects of contact time (5 min–48 h), adsorbent dosage (0.5–3 g/L), adsorbate concentration (5–400 mg/L), and the reaction kinetics, were investigated. MB concentrations above 200 mg/L achieved a maximum uptake of 90.8 mg/g after 48 h. For MB concentrations below 10 mg/L, very fast dye removal was observed, reaching 100% after 1 h. The adsorption of MB followed a pseudo-second-order model (chemisorption), and the Langmuir model better described the experimental data (monolayer adsorption). The novel strategy here reported is aligned with key Sustainable Development Goals – 6, 9, 12 and 13 – and with the concept of the Circular Economy, and these results might add value to industrial waste whose availability is still expected to grow substantially soon.

Synergetic Adsorption‐Catalysis in Potassium Oxide Modified High‐Entropy Relaxor Ferroelectrics for Efficient Dye Removal Strategy

Water scarcity caused by extreme weather events has become a global issue, leading to the necessity of wastewater recycling. Developing new materials with fast pollutant removal efficiency has become a research focus in related fields for producing clean water resources quickly and stably from wastewater. Herein, a relaxor ferroelectric type of piezoelectric high entropy perovskites, Pb(Mg,Nb,Hf,Zr,Ti)O3 (PMNHZT), is used and prepared for industrial dye removal. The synthesized PMNHZT exhibits high dark adsorption of the methylene blue dye (removal efficiency of ≈60% in 30 min) and further catalytic dye degradation (removal efficiency of ≈80–90% in 30 min) through light illumination, sonication, or a combination of both. In the dark adsorption process, K2O compounds from the synthesized environment attached to the surface of PMNHZT play a significant role in the remarkable dark adsorption by promoting a large specific surface area and more negative surface potential. Furthermore, a self‐decomposition of dye into smaller fragments by PMNHZT is also observed during dark adsorption. The piezocatalysis mechanism dominates the dye degradation process in catalytic experiments, where hydroxyl radicals are the main reactive species. Herein, a promising adsorbent and catalyst is disclosed using high‐entropy perovskites for efficient wastewater treatment.