Aqueous Waste Research Articles

Experimental and Theoretical Investigation on the Extractive Mass Transfer of Eu3+ Ions Using Novel Amide Ligands in 1-Hexyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide.

Novel amide ligands in the ionic liquid (1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) were utilized for the liquid-liquid biphasic mass transfer of Eu3+ ions from aqueous acidic waste solution. The cation exchange mechanism was found to be operative with the formation of [Eu(NO3)2L3]+ species (L = 4-chloro-N-(1-methyl-1H-pyrazol-3-yl)picolinamide). However, the presence of an inner-sphere water molecule was revealed by density functional theory (DFT) calculations. The viscosity-induced slower kinetics was evidenced during mass transfer, which was improved by increasing temperature. The process was exothermic in nature. The improvement in the kinetics of extractive mass transfer at higher temperatures is evinced by a reduction in the distribution ratio value. The spontaneity of the reaction was evidenced through the negative Gibbs free energy value, whereas the process enhances the entropy of the system, probably by releasing water molecules at least partially during complexation. The structures of bare ligands and complexes have been optimized by using DFT calculations. A high value of complexation energy, solvation energy, and associated enthalpy and free energy change reveal the efficacy in binding Eu with O and N donor atoms. In addition, natural population analysis, atoms-in-molecules analysis, and energy decomposition analysis have been employed to explore the nature of bonding existing in Eu-O and Eu-N bonds.

Molecular Simulations of Understanding Separation of Cadmium and Lead Ions from Aqueous Waste Water Using Directional Solvent Extraction

Molecular Simulations of Understanding Separation of Cadmium and Lead Ions from Aqueous Waste Water Using Directional Solvent Extraction

Effects of the multi-stress-resistant strain Zygosaccharomyces parabailii MC-5K3 bioaugmentation on microbial communities and metabolomics in tobacco waste extract.

Industrial tobacco waste was mainly treated via a reconstituted tobacco process using the paper-making method, which involves aqueous concentrated tobacco waste extract (cTWE) fermentation (aging). The fermentation was done to improve the quality of reconstituted tobacco. However, cTWE is a multi-stress environment that is characterized by low pH (about 4), as well as high sugar (above 150g/L) and nicotine (above 15g/L) content. In this study, a specific selection strategy was used to successfully isolate multi-stress-resistant bacterial or fungal strains, that exhibited positive effects on cTWE fermentation, thereby improving the quality of final products. A potential strain Zygosaccharomyces parabailii MC-5K3 was used for the bioaugmentation of cTWE fermentation and it significantly influenced the microbial diversity of the fermented cTWE. Zygosaccharomyces was observed to be the only dominant fungal genus instead of some pathogenic bacterial genera, with an abundance of over 95% after four days, and still more than 80% after a week. Meanwhile, metabolomics profiling showed significant concentration decrease with regard to some flavor-improving relative metabolites, such as 3-hydroxybenzoic acid (log2FC = -5.25) and sorbitol (log2FC = -5.54). This finding is extrapolated to be the key influence factor on the quality of the fermented cTWE. The correlation analysis also showed that the alterations in microbial diversity in the fermented cTWE led to some important differential metabolite changes, which finally improved various properties of tobacco products.

Boron and lithium recovery from aqueous solutions by ion-exchange resin stuffed electro-electrodialysis process with hydrogen production

A considerable amount of lithium is released in the wastes generated during the boron mineral enrichment process. Hence, there is a need to develop systems or processes to recover lithium and boron minerals from the waste of mining industries. In this context, electro-membrane processes have gained importance in literature recently. This study proposes a novel electro-membrane process to recover lithium and boron from an aqueous solution and simultaneous hydrogen production using an electro-electrodialysis stack composed of monovalent-anion and monovalent-cation-exchange membranes filled with ion-exchange resins. The effect of the operating parameters, such as current density, flow rate, pH type of ion-exchange resins, and initial conductivity value of the aqueous solution, on the system efficiencies are investigated. Finally, the proposed electrochemical stack's energy consumption and hydrogen production rates are calculated based on the measurements. The results reflect that maximum conductivity removal efficiency is achieved at 90% by the electro-electrodialysis process with ion-exchange resins. The highest removal efficiency of boron and lithium ions are achieved via electro-electrodialysis with ion-exchange resin as 95.1% and 99.5%, respectively. The hydrogen gas production rate is calculated as 13.55 mmol/h with the same configuration and adding ion-exchange resins to the electro-electrodialysis process improves hydrogen production by 8.6%. Finally, the net energy consumption is calculated as 6.1 kWh/m3 of synthetic wastewater. This study presents a promising method to produce hydrogen and recover valuable minerals of boron and lithium from the aqueous waste solutions.

Wet air oxidation of HTL aqueous waste

Hydrothermal Liquefaction (HTL) provides a pathway to reducing wet waste volumes and producing biofuels such as SAF or sustainable diesel. However, 20–30% of the carbon in wet-waste feed is converted to low molecular weight, water-soluble organic compounds resulting in an aqueous product requiring treatment before disposal. Extraction of fuels or chemicals from the aqueous product is an appealing but challenging route due to the low concentrations and the wide variety of the organic compounds. Herein, we report on wet air oxidation treatment of the HTL aqueous stream to reduce its complexity and increase the concentration of acetic acid in the aqueous product stream.Catalyst screening was carried out at small scale followed by batch reactor studies of selected catalysts. Oxidized products were analyzed to determine the impact of wet air oxidation on chemical oxygen demand (COD), nitrogen content, oxygen consumption and intermediate by-product formation. Batch reactor studies found that metal catalysts including WO3 and ZrO2 increased the concentration of acetic acid in the product stream by at least 10–20% compared to non-catalytic wet air oxidation. Under increasingly intense reaction conditions, COD was further reduced and acetic acid concentration increased. For example, using WO3 at 225 °C increased the concentration of acetic acid in the product stream by 72%, along with significant increases in formic acid. A continuous flow trickle bed reactor with a CeZr catalyst at temperatures ≥200 °C reduced the COD of the aqueous stream by 50% and increased acetic acid concentration by 40% (200 h run).

Phosphorus flow in production of soy protein concentrate and isolate from defatted soybean flour

AbstractImplications of excess phosphorus (P) in waste streams obtained from soy‐based protein preparation processes on the environment and their potential utilization as P‐source are two significant understudied areas. Soybean‐based protein ingredients for food products retain comparatively enhanced functional properties and are cheaper than other plant‐based proteins. Soybean protein can be extracted and utilized as a food ingredient primarily by preparing soy protein concentrates (SPC) and soy protein isolates (SPI) from soybean meal/defatted soy flour (DSF). In a typical soybean processing facility, along with the soy products and soy‐protein preparations, the recovery of phosphorus as a coproduct will enhance the economic feasibility of the overall process as the recovered P can be used as fertilizer. In this study, the SPC and SPI were prepared from the DSF following widely used conventional protocols and P flow in these processes was tracked. In SPC production, ~59% of the total P was retained with SPC and ~34% was in the aqueous waste streams. For SPI process ~24% of total P was retained with SPI and ~59% went in the waste solid residue (~40%) and aqueous streams (~19%). About 80%–89% P removal from the waste aqueous streams was achieved by Ca‐phytate precipitation. This work demonstrated that in the process of SPC and SPI preparation the phosphorus from the waste aqueous streams can be precipitated out to avoid subsequent eutrophication and the waste solid residue with ~40% P can be reused as a P‐fertilizer as other applications of this residue are unspecified.

Recent Advances in the Removal of Radioactive Iodine and Iodide from the Environment.

Iodine (I2) in the form of iodide ions (I-) is an essential chemical element in the human body. Iodine is a nonmetal that belongs to the VIIA group (halogens) in the periodic table. Over the last couple of centuries, the exponential growth of human society triggered by industrialization coincided with the use of iodine in a wide variety of applications, including chemical and biological processes. However, through these processes, the excess amount of iodine eventually ends up contaminating soil, underground water, and freshwater sources, which results in adverse effects. It enters the food chain and interferes with biological processes with serious physiological consequences in all living organisms, including humans. Existing removal techniques utilize different materials such as metal-organic frameworks, layered double hydroxides, ion-exchange resins, silver, polymers, bismuth, carbon, soil, MXenes, and magnetic-based materials. From our literature survey, it was clear that absorption techniques are the most frequently experimented with. In this Review, we have summarized current advancements in the removal of iodine and iodide from human-made contaminated aqueous waste.

Magnetic nanosorbents of γ-polyglutamic acid for removing a β-blocker from water

Metoprolol is known as one of the most frequently used β-blockers to treat hypertension, however due to its widespread use and resistance to hydrolysis, concerning amounts of this medicine are found in surface waters, causing negative impacts on the environment and human health. To date, very few water treatment plants remove metoprolol due to the ineffectiveness of conventional procedures, thus indicating the need for more efficient water treatments for eliminating traces of this drug from aqueous wastes. A promising strategy is the development of magnetic assisted sorbents with a high surface area and adequate chemical modification aimed at the target pollutant, offering the possibility of total removal from water supplies and thus limiting potential environmental impacts. In this context, the purpose of this work was to investigate the application of magnetic Fe3O4 nanoparticles coated with silica and γ-polyglutamic acid to capture metoprolol dissolved in water. The synthesized sorbents consisted of magnetite nanoparticles with an average size of 55.8 nm, coated with a layer of amorphous silica covalently bound to γ-polyglutamic acid, thus exposing carboxylate surface active sites, which favor electrostatic interactions with metoprolol. As the γ-polyglutamic acid sources, two types of materials with distinct amounts in the biopolymer (30% and 92%) have been investigated. The adsorption of metoprolol by the nanosorbents γ-PGA/Fe3O4 was evaluated by means of adsorption isotherms and theoretical adsorption models. Freundlich and Langmuir models provide an accurate description of the isotherm, and the compound’s maximum adsorption capacity was 571.6 mg g−1. Noteworthy, the magnetic nanosorbents prepared using γ-polyglutamic acid 30% and 92% have shown comparable performances, which makes this process also economically attractive considering that a low-cost raw material can be used.

Assessment of the Impact of a New Industrial Discharge on an Urban Wastewater Treatment Plant: Proposal for an Experimental Protocol

Assessing the compatibility of industrial discharges with the biological process of a municipal wastewater treatment plant (WWTP) may represent a critical task. Indeed, either focusing only on chemical characterization or ecotoxicity tests designed to assess the impact on surface waters may lead to questionable or misleading conclusions. The feasibility of an industrial connection to the sewer should better take into account the features of the downstream WWTP, in particular by studying the potential effects on the biomass of that specific plant. With this aim, a multi-step experimental protocol applicable by water utilities has been proposed: (step 1) calculation of the flow rate/load ratio between industrial discharge (ID) and urban wastewater (WW); (step 2) analysis of the modified operating conditions of the biological stage; (step 3) experimental assessment of the impact of the ID on the WWTP biomass by means of respirometric tests. An application of this protocol is presented in this work as a case study, namely a new ID (average flowrate 200 m3 d−1) coming from an aqueous waste treatment plant (AWTP) to be connected to the public sewer. The integrated evaluation of results showed that no negative impacts could be expected on the downstream urban activated sludge WWTP (treating a flow rate of around 45,000 m3 d−1).

Occurrence and formation of environmentally persistent free radicals in incineration and their impact on soil and water

Incineration is a thermal waste treatment technique that can be understood as a controlled combustion process with the primary objective of volume reduction of waste mass. Combustible waste including gaseous, aqueous, muddy, molten, and solid waste is typically deal with incineration at temperature ranges from 750 to 1200 °C. End products of incineration include a considerable amount of particulate matter (PM) and pollutants. Particulate matter released from the incineration process plays an important role in forming environmentally persistent free radicals (EPFRs) which are the most toxic and stable substance emitted from the incinerator. Other major compounds released during the incineration process are dioxins, polychlorinated biphenyls, polychlorinated naphthalene, chlorinated benzenes, and polycyclic aromatic hydrocarbons (PAH). Although incineration is significantly used to control the waste crisis but emissions of toxic substances from an incinerator have various health impacts on the environment and humans. Long exposures to these hazardous compounds lead to respiratory and cardiovascular diseases. These toxic compounds participate in various redox activities as well as metal complexation events and deteriorate the physiochemical parameter of soil and water. The aim of the present study is to summarize the existing knowledge regarding the formation of harmful compounds released during waste incineration and major environmental challenges associated with them.

Nitrile derivative functionalized graphene oxide membranes for efficient separation of strontium from aqueous waste

Graphene oxide (GO) layers were functionalized with nitrile derivatives through acetonitrile vapour exposure and repercussions of N-functionalization on strontium (Sr(II)) adsorption performance of GO membranes were evaluated. Acetonitrile exposure reduces oxygen content of GO, integrates nitrile (CN), amine (–NH2), multiple highly reactive N-moieties on GO yet, preserves intactness of GO lamellar structures. Nitrile derivative functionalization escalates Sr(II) adsorption ability of GO membranes by nearly two fold and an optimal sorption of ∼610 mg/g was obtained at limited GO mass (∼0.1 mg) and Sr(II) concentration of 60–100 µg/mL. N-modified GO membranes displayed confinement of ∼70% percolated Sr2+ ions, considerable Sr(II) adsorption of ∼200 mg/g even after six filtration cycles, limited desorption of 7–24% and competent Sr (II) uptake in presence of Mg2+/Ba2+ ions. Inferences obtained from N-integration and Sr(II) adsorption studies were validated through benzonitrile/nitromethane subjected GO membranes as well, where, adequately amended nitromethane-GO membranes exhibited an enhanced Sr(II) sorption of ∼485 mg/g. Pronounced Sr(II) adsorption performances witnessed for variety of N-GO membranes in the present work re-emphasize the eminence of N-groups in Sr(II) capture, efficacy of N-reagent selection, significance of vapour exposure method and demonstrate the potential of N-modified GO membranes in Sr(II) separation.

Selective permeation up a chemical potential gradient to enable an unusual solvent purification modality

The need for energy-efficient recovery of organic solutes from aqueous streams is becoming more urgent as chemical manufacturing transitions toward nonconventional and bio-based feedstocks and processes. In addition to this, many aqueous waste streams contain recalcitrant organic contaminants, such as pharmaceuticals, industrial solvents, and personal care products, that must be removed prior to reuse. We observe that rigid carbon membrane materials can remove and concentrate organic contaminants via an unusual liquid-phase membrane permeation modality. Surprisingly, detailed thermodynamic calculations on the chemical potential of the organic contaminant reveal that the organic species has a higher chemical potential on the permeate side of the membrane than on the feed side of the membrane. This unusual observation challenges conventional membrane transport theory that posits that all permeating species move from high chemical potential states to lower chemical potential states. Based on experimental measurements, we hypothesize that the organic is concentrated in the membrane relative to water via favorable binding interactions between the organic and the carbon membrane. The concentrated organic is then swept through the membrane via the bulk flow of water in a modality known as "sorp-vection." We highlight via simplified nonequilibrium thermodynamic models that this "uphill" chemical potential permeation of the organic does not result in second-law violations and can be deduced via measurements of the organic and water sorption and diffusion rates into the carbon membrane. Moreover, this work identifies the need to consider such nonidealities when incorporating unique, rigid materials for the separations of aqueous waste streams.

Reactive extraction of protocatechuic acid by di-n-octylamine and optimisation with Box–Behnken design

ABSTRACT Protocatechuic acid (PCA) is typically produced by microbial fermentation. Its separation from fermentation broth or aqueous waste streams is of great importance. This study aimed to recover PCA by a secondary amine namely di-n-octylamine (DOA). Three organic solvents, namely isobutyl methyl ketone, propyl acetate and linalool, were used with DOA. Important extraction parameters were optimised by response surface methodology. DOA/isobutyl methyl ketone system showed 95.84% extraction efficiency under the optimum conditions. The maximum E% of the DOA/propyl acetate system was 86.73%. The maximum E% of the DOA/linalool system was 81.71%. Additionally, a thermodynamic study was carried out, and the reactions were endothermic. Highlights Protocatechuic extraction by di-n-octylamine has been done first in the literature. Different kinds of solvents have been used to solve di-n-octylamine. Useful information is obtained for the design of protocatechuic acid reactive extraction.

Grasping pros and cons of SiO2 proximal to Lewis acidic metal cations in activating H2O2 heterolysis under electric environments

Lewis acidic metals (Mδ+) cleave H2O2 to evolve •OH used for fragmenting aqueous wastes. Mδ+ species are situated near SiO2 and generate interfacial Mδ+-SiO2 domains, where Mδ+ species can avoid aggregation, retain •OH productivity with minimal leaching via chelation to the –OH of SiO2, elevate the collisions between Mδ+ and H2O2 or between •OH and aqueous pollutants via confinement, and destabilize contaminants via electron (e-) transfer. The merits of SiO2 stated earlier, however, remain abstract and only partially clarified. Herein, interfacial Niδ+-SiO2 domains were created on SiO2-modified NiS/Ni9S8 (NiS/Ni9S8-SiO2) to elaborate the aforementioned advantages of SiO2 under electric conditions, where it was hypothesized that e- transfer can occur from O2–/di-sulfide (S22-)/poly-sulfide (SN2-) to Niδ+ species. SiO2 was verified to increase the amount of Niδ+ speices for NiS/Ni9S8-SiO2 and reduce their Lewis acidic strengths, which was conducive to lowering the energy barrier required for H2O2 dissection. SiO2 was demonstrated to hardly promote the collisions of Niδ+ with H2O2 because of the hydrogen bonding of H2O2 with SiO2, reduce Niδ+ leaching via e- acceptance from O2–/S22-/SN2- rather than via –OH chelation, while making e- migration from Niδ+ to aqueous organics scarcely compelling.

Simulation Studies on Recovery of Acetonitrile from Aqueous Acetonitrile Waste from Pharmaceutical Processes

This paper presents simulation studies on the recovery of Acetonitrile from aqueous Acetonitrile waste from pharmaceutical processes. The focus is on atmospheric distillation in two sequential columns to understand the separation feasibility of the system; the first column produces a distillate of azeotropic composition, which is mixed with a fresh stream and fed to a second column, which produces a 99.9% pure Acetonitrile in the residue. The effect of reflux ratio, reboiler duty and the fresh stream flowrate on the purity of the product is analyzed. The study was performed using steady state simulator Aspen Plus, version 11.1. The simulation results indicate that it is possible to obtain a product of 99.9% w/w Acetonitrile from a 1:1 feed with a recovery of ~ 60%.

Determination of triacetone triperoxide (TATP) traces using passive samplers in combination with GC-MS and GC-PCI-MS/MS methods

The use of organic peroxides for the preparation of homemade explosives (HMEs) is common among terrorists due to inexpensive precursor chemicals and simple synthetic procedures. Triacetone triperoxide (TATP) is the most notable peroxide explosive, and has been deployed in several terrorist attacks as explosive filling of improvised explosive devices (IEDs). Forensic identification of TATP in pre-blast and post-blast residues, including on-site analysis, poses significant analytical challenges and induces demand for practicable and sensitive detection techniques. This work presents a concept suitable for laboratory and on-site identification of TATP residues in liquid samples (aqueous TATP synthetic waste) and in gas phase. It is based on TATP enrichment from the aqueous or gas phase using different types of passive samplers (polydimethylsiloxane (PDMS) sampling rods and activated carbon sampling tubes (ACST)) and subsequent identification of the explosive by gas chromatography-mass spectrometry (GC-MS) or GC with positive chemical ionization and tandem MS (GC-PCI-MS/MS) analytical techniques. Additionally, investigation of the stability of TATP in aqueous solutions and of the stability of enriched TATP in passive samplers under different storage conditions, as well as development of TATP re-extraction procedures from passive samplers have been performed in this study. The practical use of passive samplers was demonstrated during and after TATP production processes. Moreover, post-blast sampling of TATP under different conditions of controlled blasting events was investigated using the passive sampling concept.

Inorganic Sorbents for Wastewater Treatment from Radioactive Contaminants

The article presents the distribution coefficient (Kd) values of 137Cs and 90Sr tracer radionuclides in solutions of sodium and calcium salts for a wide range of commercially available inorganic sorbents: natural and synthetic aluminosilicates, manganese, titanium and zirconium oxyhydrates, titanium and zirconium phosphates, titanosilicates of alkali metals, and ferrocyanides of transition metals. The results were obtained using a standard technique developed by the authors for evaluating the efficiency of various sorption materials towards cesium and strontium radionuclides. It was shown that bentonite clays and natural and synthetic zeolites are the best for decontaminating low-salt natural water from cesium radionuclides, and ferrocyanide sorbents are the choice for decontaminating high-salt-bearing solutions. The manganese (III, IV) oxyhydrate-based MDM sorbent is the most effective for removing strontium from natural water; for seawater, the barium silicate-based SRM-Sr sorbent is the first-in-class. Results of the study provide a possibility of making a reasonable choice of sorbents for the most effective treatment of natural water and technogenic aqueous waste contaminated with cesium and strontium radionuclides.

Reclamation of wastewater polluted with antihypertensive drug residues by the biological+solar-photocatalytic sequential treatment plant

The quality of polluted wastewater processed by conventional Wastewater Treatment Plants (WWTPs) is in some cases insufficient to reach the degree of purity required. Pharmaceuticals are frequently identified in the aquatic environment, owing to their constant release from WWTPs. Thus, in recent years, they are cataloged as pseudo-persistent pollutants having been recognized as potentially harmful to public health and environmental concern. This work has focused on the removal of 3 antihypertensive pharmaceuticals (furosemide, irbesartan, and valsartan) from aqueous waste solutions using a sequential biological-photocatalytic (TiO2/Na2S2O8) treatment under natural sunlight. Pharmaceutical residues were isolated from water by solid phase extraction (SPE) and analyzed by HPLC-QqQ-MS2. Biodegradation was greater than 65% and 70% for irbesartan and furosemide, respectively, while valsartan was highly biodegradable (> 96%). Next, photocatalytic treatment was applied and just 200 kJ m-2 was required to remove 90 % of micropollutants residues from the effluent. Therefore, the coupling of biological treatment to solar heterogeneous photocatalysis constitutes a valuable instrument to detoxify polluted wastewater.

Sulfide Removal by Catalitic Oxidation From Rayon Waste

Catalytic oxidation of spent sulfidic caustic consist of SH- ion or NaHS compound by H 2 O2 in neutral or acidic solution to elemental sulphur may provide a convenient and economical method for the control of sulphide wastes and their associated odors at pulp, paper and textile industry. Oxidation of sulfide in rayon waste by hydrogen peroxide was investigated in the presence of ferric sulfate catalyst. Kinetic equations and activation energies of H 2 O2 and SH- ion to total sulphur and sulphate in rayon waste for catalytic oxidation reaction were calculated based on the experimental results. For the removal of sulfide from sulfide solution the most common process involves its catalytic oxidation to a more benign form sulfate. The rate of sulfidic catalytic oxidation was found higher at lower initial sulphide concentration and the rate of sulphide catalytic oxidation was found directly proportional to loading and hydrogen peroxide addition. Optimum total sulphide concentration was achieved when sulphide solutions in the presence of H 2 O 2 in the ratios SH-/H 2 O 2 1:4.2. The potential user of H 2 O 2 determine the optimal conditions for control of odor, corrosion and waste treatment cost due to sulfide consisting of sulphur ion, sulphate ion, etc. The catalytic oxidation of sulphides into sulphates by H 2 O 2 may be applied directly to aqueous wastes containing these odorants

Extraction of lipids from microalgal slurries with liquid CO2

Traditional methods for lipid extraction from microalgae achieve high yields, but at the cost of energy-intensive drying of the microalgae before extraction and the toxicity and price of the extraction solvents. Liquid carbon dioxide (lCO2) is shown to successfully extract lipids from aqueous microalgal slurries. The rate and yield were dependent on the extraction conditions, including lCO2 flow rate, reaction time, lCO2 pressure, microalgae cocentration, and mixing. Higher concentrations of microalgae resulted in a decrease in percent yield, likely due to mass transfer limitations when mixing the lCO2 and algae. However, increasing the flow rate of lCO2 (1.5 to 4 mL/min) or the pressure (7.5 to 17.5 MPa) improved the extraction yield and the rate of extraction. Liquid CO2 does not contaminate the aqueous waste stream, does not require the algae to be completely dried and does not require as much pressure as supercritical CO2.