Real Wastewater Samples Research Articles

Removal of triclocarban from treated wastewater using cell-immobilized biochar as a sustainable water treatment technology

Triclocarban (TCC), an emerging endocrine disruptor, has been commonly found in municipal treated wastewater. Pseudomonas fluorescens MC46 (MC46), an effective TCC-degrading bacterium, could be applied to remove TCC from wastewater. In addition, application of a cell immobilization technique could possibly enhance its removal performance. This study examined microbial cells immobilized on waste biochar (from wood vinegar production) as a highly effective advanced wastewater treatment unit for TCC removal. TCC removal was investigated from real wastewater samples using the following treatments: biochar only, cell-immobilized biochar, and free cell systems in batch (short-term) and semi-batch (long-term) modes. The TCC adsorption capacities of original and potassium hydroxide-modified biochars (no cells) were 8.43 and 9.17 mg/g, respectively. During the batch experiment, the cell-immobilized modified biochar exhibited the highest TCC removal, 79.80%, in the model TCC solution. Five-cycle semi-batch experiments were utilized to investigate the reusability and performance of the treatment systems. After five cycles, the cell-immobilized modified biochar still achieved stable TCC removal (52%) due to the integration of adsorption and biodegradation. Free MC46 cells and biochars (no MC46 cells) only removed 32% and 2% of TCC, respectively, due to cell washout/death and sorbent exhaustion. This important work clearly demonstrates the significant potential for the future utilization of cell-immobilized biochars in a sustainable wastewater treatment system. Furthermore, the use of renewable agro-industrial wastes aid in the development of a strong circular bio-based economy.

Preconcentration of rifampicin prior to its efficient spectroscopic determination in the wastewater samples based on a nonionic surfactant.

Every year, tuberculosis affects the lungs of millions of people and rifampicin is the commonly used medicine for its treatment due to its antibiotic nature. The frequent use of rifampicin may lead to its increased concentration in the water resources. This research work is focused on the cloud point extraction (CPE) procedure for the preconcentration of rifampicin prior to its determination in water. The UV/vis spectrophotometric method was adapted for the measurement of rifampicin content after the phase separation. Triton-X 100 was used as the nonionic surfactant which contains hydrophilic polyethylene chain feasible for the extraction of analyte. Various analytical parameters that can affect the extraction efficacy were optimized to achieve linearity of the proposed method in the concentration range of 3.54–81.41 mgL–1. The Limit of detection and quantification were 1.261 and 4.212 mgL–1, respectively. The Preconcentration factor was 40 with relative standard deviation (%RSD) of 2.504%. The standard addition methodology was adopted for the validation of this procedure and effectively applied for the determination of rifampicin in real wastewater samples.

Fabrication of Membrane Sensitive Electrodes for the Validated Electrochemical Quantification of Anti-Osteoporotic Drug Residues in Pharmaceutical Industrial Wastewater.

Accurate and precise application of ion-selective electrodes (ISEs) in the quantification of environmental pollutants is a strenuous task. In this work, the electrochemical response of alendronate sodium trihydrate (ALN) was evaluated by the fabrication of two sensitive and delicate membrane electrodes, viz. polyvinyl chloride (PVC) and glassy carbon (GC) electrodes. A linear response was obtained at concentrations from 1 × 10−5 to 1 × 10−2 M for both electrodes. A Nernstian slope of 29 mV/decade over a pH range of 8–11 for the PVC and GC membrane electrodes was obtained. All assay settings were carefully adjusted to obtain the best electrochemical response. The proposed technique was effectively applied for the quantification of ALN in pure form and wastewater samples, acquired from manufacturing industries. The proposed electrodes were effectively used for the determination of ALN in real wastewater samples without any prior treatment. The current findings guarantee the applicability of the fabricated ISEs for the environmental monitoring of ALN.

Treatment of textile matrices using Fenton processes: influence of operational parameters on degradation kinetics, ecotoxicity evaluation and application in real wastewater

Since conventional processes for treating textile effluents have limitations, this work aimed to investigate the application of advanced oxidation technology in this type of matrix. Initially, for a textile dyes mixture in solution, the photo-Fenton/sunlight process proved to be the most efficient among other systems tested. During the tests it was found that the degradation kinetics depends of the pH and catalyst and oxidant concentrations. After 60 min under optimized conditions, the color was reduced by 98.19%, with 92.52% organic matter conversion. Ecotoxicity tests with the Lactuca Sativa vegetable indicated that the dyes were not totally oxidized to inert compounds, although the treated solution did not cause a significant toxic effect for this species. In the second stage of the research, the photodegradation in real samples of textile wastewater was evaluated. The efficiency of the photo-Fenton/sunlight process was lower than that obtained for the dyes solution, a fact attributed to the greater complexity of the real matrix. However, the data also indicated that the combination of coagulation/flocculation and advanced oxidation processes is the most suitable methodology to reduce the fraction of biodegradable compounds. In summary, research has revealed that photocatalytic degradation of dyes through advanced oxidation is an efficient treatment.

Use of charcoal from gasification residues in adsorption pilot plant for the practical application of circular economy in industrial wastewater treatment

In the present work, the charcoal obtained after the gasification of wood residues was tested in a pilot adsorption unit to evaluate the feasibility of treating real textile wastewater on a semi-industrial scale. The aims were to evaluate the global performance of the adsorption column in the pilot system using a methylene blue (MB) solution, and then a real sample of textile wastewater. Two charcoal samples, which were a by-product of the gasification process, were obtained, characterized, and tested with a MB dye solution. The experimental adsorption capacity of the fixed-bed was near 34 mg.g−1 in both cases, and the overall removal efficiency of the column was >91%. Experimental data were fitted according to the Thomas and Adams-Bohart models. The pilot plant proved to be effective for improving the treatment of real textile wastewater, regarding the removal of color and part of organic matter, verified by the evolution of chemical oxygen demand over time. The cost to operate the pilot plant was calculated, and the contribution to the circular economy was considered. The pilot unit was promising for improving the wastewater treatment process, adding value, and giving a new purpose to a waste that normally would be disposed in the environment.

Investigating the potential of ammonium retention by graphene oxide ceramic nanofiltration membranes for the treatment of semiconductor wastewater

Ceramic membranes with high chemical and fouling resistance can play a critical role in treating industrial wastewater. In the present study, we demonstrate the fabrication of graphene oxide (GO) assembled ceramic nanofiltration (NF) membranes that provide effective ammonium retention and excellent fouling resistance for treating semiconductor wastewater. The GO-ceramic NF membranes were prepared via a layer-by-layer (LbL) assembly of GO and polyethyleneimine (PEI) on a ceramic ultrafiltration (UF) substrate. The successful fabrication of the GO-ceramic NF membranes was verified through surface characterization and pore size evaluation. We also investigated the performance of GO-ceramic NF membranes assembled with different numbers of bilayers for the rejection of ammonium ions. GO-ceramic NF membranes with three GO-PEI bilayers exhibited 8.4- and 3.2-times higher ammonium removal with simulated and real semiconductor wastewater, respectively, compared to the pristine ceramic UF substrate. We also assessed flux recovery after filtration using real semiconductor wastewater samples to validate the lower fouling potential of the GO-ceramic NF membranes. Results indicate that flux recovery increases from 39.1 % in the pristine UF substrate to 71.0 % and 90.8 % for the three- and ten-bilayers GO-ceramic NF membranes, respectively. The low-fouling GO-ceramic NF membranes developed in this study are effective and promising options for the removal of ammonium ions from semiconductor wastewater.

Preparation and Characterization of Novel Magnesium Composite/Walnut Shells-Derived Biochar for As and P Sorption from Aqueous Solutions

Elevated or unnatural levels of arsenic (As) and phosphorus (P) concentrations in soils and waterbodies from anthropogenic sources can present significant hazards for both natural ecosystems and human food production. Effective, environmentally friendly, and inexpensive materials, such as biochar, are needed to reduce mobility and bioavailability of As and P. While biochar features several physicochemical properties that make it an ideal contaminant sorbent, certain modifications such as mineral-impregnation can improve sorption efficiencies for targeted compounds. Here, we conducted sorption experiments to investigate and quantify the potential utility of magnesium (Mg) for improving biochar sorption efficiency of P and As. We synthesized a Mg-modified walnut shells-derived biochar and characterized its ability to remove As and P from aqueous solutions, thereby mitigating losses of valuable P when needed while, at the same time, immobilizing hazardous As in ecosystems. SEM-EDX, FTIR and elemental analysis showed morphological and functional changes of biochar and the formation of new Mg-based composites (MgO, MgOHCl) responsible for improved sorption potential capacity by 10 times for As and 20 times for P. Sorption efficiency was attributed to improved AEC, higher SSA, chemical forms of sorbates and new sorption site formations. Synthetized Mg-composite/walnut shell-derived biochar also removed >90% of P from real samples of wastewater, indicating its potential suitability for contaminated waterbody remediation.

Validated Simultaneous Gradient Ultra-Performance Liquid Chromatographic Quantification of Some Proton Pump Inhibitor Drug Residues in Saudi Pharmaceutical Industrial Wastewater.

Monitoring and quantification of active pharmaceutical ingredients (APIs) in the environment constitute important and challenging tasks, as they are directly associated with human health. Three commonly used proton pump inhibitors (PPIs), namely, omeprazole sodium (OMP), pantoprazole sodium (PNT), and lansoprazole sodium (LNZ) are well separated and quantified using ultra-performance liquid chromatography (UPLC) in pharmaceutical industrial wastewater. The separation of the studied drugs was performed on a stationary phase with a WatersTM column (100 × 2.1 mm, 1.7 µm). The mobile phase was composed of methanol:0.05 M potassium dihydrogen phosphate buffer (adjusted to pH 7.5 using NaOH) (50:50, v/v). The elution process was done in gradient mode by changing the relative proportions of the mobile phase components with time to get an optimum separation pattern. The flow rate of the developing system was adjusted to 0.8 mL/minute. Detection of the separated drugs was performed at 230 nm. The studied drugs were quantified in the concentration range of 10–200 ng/mL for all drugs. The cited method was fully validated according to the international conference on harmonization (ICH-Q2B) guidelines, then it was applied successfully for quantification of the studied PPIs in real wastewater samples after their solid phase extraction (SPE).

Green synthesis of zinc oxide nanoparticles by Ziziphus jujuba leaves extract: Environmental application, kinetic and thermodynamic studies

This research reports, for the first time, the eco-friendly green synthesis of zinc oxide nanoparticles (ZnO NPs) using Ziziphus jujuba leaves extract assisted by microwave irradiation. Eco-friendly prepared ZnO NPs were characterized by different techniques, and the results confirmed the formation of hexagonal wurtzite ZnO nanoparticles with different particle sizes. The prepared ZnO NPs were then used for the adsorption and removal of two different azo dyes; methyl orange (MO), and methylene blue (MB), as well as toxic Pb(II) ions, from a model solution and real samples. The influence of experimental conditions was explored; ZnO NPs mass, contact time, solution pH, solution ionic strength, and solution temperature, and the results showed that most of the MB, MO, and Pb(II) could be removed from the model solution within a few minutes, at ambient conditions. The experimental removal capacities of 5.21, 2.57, and 596 mg of MO, MB, and Pb(II) per gram of microwave-assisted green ZnO NPs (MWG ZnO NPs), respectively, were obtained. The removal of the MB, MO, and Pb(II) using ZnO NPs was studied kinetically and thermodynamically, and the results showed that the experimental data were best fitted using the pseudo-second-order kinetic models, with rate constants of 0.165, 0.364, 247 × 10–6, for the MO, MB, and Pb(II), respectively. The thermodynamics study showed that the process was spontaneous, with an exothermic nature. Finally, the prepared ZnO NPs were used for the removal of MB, MO, and Pb(II) in real wastewater samples, and high removal efficiency was presented. The regeneration and reusability were explored, and the results revealed the applicability of using the MWG ZnO NPs for the removal of MB, MO, and Pb(II) for five consecutive cycles.

Adsorption of Biogenic Amines from Synthetic and Real Wastewater using a Zwitterion‐Functionalized Blast Furnace Slag

AbstractBlast furnace slag functionalized with sulfamic acid (zwitterion) shows an extraordinary potential for the removal of biogenic amines from spiked water and real wastewater samples. The functionalized slag is characterized using scanning electron microscopy‐energy dispersive spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), and acid site density test. Its performance toward the removal of selected biogenic amines (putrescine, tyramine, and 2‐phenylethylamine) is evaluated at different experimental conditions that include pH, contact time, adsorbent dosage, and initial concentration. The central composite experimental design is employed in investigating the effect of these individual factors and their interactions. The adsorption experiment results fit both the Langmuir isotherm model and pseudo‐second‐order kinetic model based on the computed high coefficient of determination (R2) values. Maximum adsorption capacity values of 80.64 mg g−1 for 2‐phenylethylamine, 12.5 mg g−1 for putrescine, and 64.52 mg g−1 for tyramine are estimated from the Langmuir isotherm model. Hydrogen bonding interaction between the S═O groups of the functionalized slag and protonated amino groups of biogenic amines is speculated as the possible mechanism of adsorption. The prepared functionalized slag also exhibits good adsorptive removal of biogenic amines in a date palm fruit processing industrial wastewater sample.

Synthesis of new functionalized Calix[4]arene modified silica resin for the adsorption of metal ions: Equilibrium, thermodynamic and kinetic modeling studies

In this study, a new efficient resin-based material has been synthesized through the surface modification of silica by functionalized calix[4]arene and applied for the adsorption of metal ions from aqueous media. The synthesis of functionalized calix[4]arene modified silica (FCMS) resin was characterized by FTIR, CHNS, BET surface area, SEM analyses. The FCMS resin has high thermal and chemical stabilities that were checked by the thermogravimetric analysis and various acidic/basic conditions. The efficiency of the FCMS resin was checked by performing a set of batch experiments under optimized parameters such as concentration of the metal solution, pH, resin dosage, time, temperature, and competitive adsorption in mixed solutions. The results showed that better adsorption has been achieved at pH 7, with 25 mg adsorbent dosage and 10 min contact time. The equilibrium kinetic study showed that the metal adsorption follows the pseudo 2nd order kinetic model with quite high coefficients of determination values (R2 > 0.99). The experimental data have been validated by applying three adsorption isotherm models and the results revealed that the Freundlich isotherm model (R2 > 0.99) was the best fit for the adsorption of Cu2+, Pb2+, and Cd2+ ions. However, the sorption energy calculated from the D-R isotherm model for Cu2+, Pb2+, and Cd2+ ions suggested that an ion-exchange mechanism is involved on the surface of the FCMS resin. The thermodynamic data demonstrated that the reaction is spontaneous and endothermic. The FCMS resin was also applied on real wastewater samples and the results demonstrated that the resin has a good ability to treat metal-contaminated wastewater.

Nitrification Process in a Nuclear Wastewater with High Load of Nitrogen, Uranium and Organic Matter under ORP Controlled

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.

Adsorptive removal of cefixime using a novel adsorbent based on synthesized polycation coated nanosilica rice husk

We report the first study of adsorption of a strong polycation, poly(3-methacryloylamino propyl-trimethylammonium chloride) (PMAPTAC) on nanosilica (nano-SiO2) extracted from rice husk. PMAPTAC was successfully synthesized and characterized by 1H-nuclear magnetic resonance (1H NMR) and gel-permeation chromatography (GPC) methods. PMAPTAC characteristics were found to be Mn = 1.61 × 105, Mw = 2.16 × 106, Mw/Mn = 13.4. Beta-lactam cefixime (CEF) removal was dramatically enhanced after polymer coating by pre-adsorption of PMAPTAC on nano-SiO2. The new adsorbent was dubbed PMAPTAC coated nano-SiO2 (PCNS). Required time for adsorption, PCNS dosage, pH, and KCl concentration were thoroughly optimized for CEF removal and achieved at 120 min, 10 mg/mL, 4, and 1 mM, respectively. A two-step model can be used to fit the PMAPTAC on nano-SiO2 and CEF on PCNS isotherms at different ionic strengths. Adsorption kinetics of CEF on PCNS appears to be pseudo-second-order. CEF removal using PCNS reached 89%, saturating at 10.9 mg/g. The driving force for CEF adsorption on PCNS was primarily Coulombic interaction of negative CEF species and positive surface charge of PCNS. After three reuses, CEF elimination was still greater than 85%. The influence of some organics on CEF treatment using PCNS was insignificant while CEF removal from a real hospital wastewater sample was greater than 70%. Our study indicates that a hybrid and new adsorbent based on nano-SiO2 rice husk with pre-adsorption with PMAPTAC is useful for antibiotic removal from wastewater.

Highly efficient and fast batch adsorption of orange G dye from polluted water using superb organo-montmorillonite: Experimental study and molecular dynamics investigation

Natural montmorillonite (Mt) is modified with cetyltrimethylammonium bromide (CTAB) for obtaining an organoclay. The physicochemical properties of Mt and CTAB-modified Mt (CTAB@Mt) are characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, nitrogen sorption, and thermogravimetric/differential thermal analysis. The CTAB@Mt is used as an adsorbent for the removal of orange G anionic dye from aqueous solutions. The adsorption process is examined as a function of adsorbent amount, contact time, temperature, pH, and initial dye concentration. The kinetic study indicates that the adsorption equilibrium of orange G dye onto CTAB@Mt is reached after 30 min and fits well to a pseudo-second-order kinetic model. Also, the adsorption isotherm data is best fitted by a Langmuir model, with the maximum adsorption capacity calculated using the non-linear form of the Langmuir isotherm being 167 mg g−1 at 298 K. The statistical physics model shows that the OG dye could be adsorbed with a non-parallel orientation on the surface of CTAB@Mt. Finally, CTAB@Mt is successfully employed for the treatment of a real wastewater sample from the textile industry. Molecular dynamics simulations are performed to investigate, on one hand, the structural properties of CTAB intercalated into the 2:1 layered Mt and coated on its external surface, and on the other hand, to provide atomic-level insight on the adsorptive characteristics of orange G dye on CTAB@Mt.

Electrocoagulation applied for the removal of microplastics from wastewater treatment facilities

• Electrocoagulation was tested for the removal of microplastics. • In real wastewater samples, microplastic removal efficiencies of 98.6% were achieved. • Results showed that the electrocoagulation process is an effective process for microplastic removal. • The blanket sludge floated after the electrocoagulation could be easily removed by overflow or skimming. This study evaluated the efficacy of electrocoagulation methods for the removal of microplastics using both synthetic solutions and wastewater samples. The experiments were performed with commercial polyester microplastic in batch reactors. Current density (1.92–8.07 mA/cm 2 ), pH (2–7), microplastic size range (25–1500 μm), and electrolysis time (0–90 min) were the variables used to assess the process. When using synthetic solutions with pH values of 4 and 7 and current densities of 2.88 and 8.07 mA/cm 2 , the microplastic removal efficiency was at least 99% in all cases. Measurement of Particle Image velocity (PIV) and analysis of Scanning Electron Cryomicroscopy (Cryo-SEM) were used as monitoring tools for tracking the activity of the hydrogen gas bubbles. The lowest estimated operational costs were obtained by using a current density of 2.88 mA/cm 2 and an initial pH of 4. Using real wastewater samples, the removal efficiency of microplastics was 96.5%. In addition, 92.2% of COD and 88.8% of thermotolerant coliform colonies were removed. The results of the study showed that electrocoagulation effectively can remove microplastics from wastewater streams at low operational costs while simultaneously reducing both COD and thermotolerant coliforms.

Development of a Highly Sensitive Imprinted Electrochemical Sensor for the Detection of Hydrocortisone in Wastewater

The existence of hydrocortisone in water resources is a serious threat to human health. However, the rapid and sensitive detection methods for hydrocortisone in wastewater are still lacking. Meanwhile, due to the weak redox activity of hydrocortisone, electrochemical technique cannot be used to detect hydrocortisone directly. Therefore, molecularly imprinted technique combined with prussian blue nanoparticles was synthesized for detecting HC indirectly in this work. We fabricated a novel and highly sensitive molecularly imprinted sensor based on the polydopamine/electro-reduced graphene oxide, which was used for the specific recognition of hydrocortisone in water samples. The prussian blue nanoparticles were introduced as probes to reflect the concentration of the target. The morphology of the prepared sensors was characterized by the scanning electron microscopy. And the feature of the imprinted electrode was performed by the cyclic voltammetry and differential pulse voltammetry. Under the optimal experimental conditions, the relative current signal of prussian blue decreased linearly with the increase of hydrocortisone concentration with a limit of detection 0.006 nM. Moreover, the imprinted sensor had a much higher affinity towards hydrocortisone than other analogues. Then, this system was successfully applied to determine hydrocortisone in real wastewater samples with workable results.

Removal of Phenol from Aqueous Solution Using Internal Microelectrolysis with Fe-Cu: Optimization and Application on Real Coking Wastewater

Fe-Cu materials were synthesized using the chemical plating method from Fe powder and CuSO4 5% solution and then characterized for surface morphology, composition and structure by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The as-synthesized Fe-Cu material was used for removal of phenol from aqueous solution by internal microelectrolysis. The internal electrolysis-induced phenol decomposition was then studied with respect to various parameters such as pH, time, Fe-Cu material weight, phenol concentration and shaking speed. The optimal phenol decomposition (92.7%) was achieved under the conditions of (1) a pH value of phenol solution of 3, (2) 12 h of shaking at the speed of 200 rpm, (3) Fe-Cu material weight of 10 g/L, (4) initial phenol concentration of 100.98 mg/L and (5) at room temperature (25 ± 0.5 °C). The degradation of phenol using Fe-Cu materials obeyed the second-order apparent kinetics equation with a reaction rate constant of k of 0.009 h−1L mg−1. The optimal process was then tested against real coking wastewater samples, resulting in treated wastewater with favorable water indicators. Current findings justify the use of Fe-Cu materials in practical internal electrolysis processes.

Antiviral amphiphilic membranes based on the organometallic compound for protein removal from wastewater with fouling-resistant

Antiviral ultrafiltration membranes (UF) were successfully fabricated using amphiphilic polyvinylchloride-co-acrylic acid) (PVC-AA), which were incorporated with organometallic compound manganese acetylacetonate Mn(acac)3. Non-solvent induced phase separation (NIPS) method was used to prepare the UF membrane based on PVC-AA. Fabricated membranes were characterized by different analytical methods. The fabricated membranes (PVC-AA/ Mn(acac)3) provided the highest removal percentage for proteins when compared to the neat amphiphilic (PVC-AA). The hydrophilicity and antifouling properties of the membranes were improved with increasing load of manganese acetylacetonate Mn(acac)3 in the polymeric solution to 1%. The membrane with 1 wt% Mn(acac)3 (UF3) exhibited the best antifouling properties using bovine serum albumin 1 g.L−1and sodium alginate 2 g.L−1 and a real sample of wastewater namely ~ 99% of flux recovery ratio. PVC-AA- Mn(acac)3 provided antifouling and antiviral properties. The viral test using real sewage wastewater indicated that the membranes UF 2 and UF3 removes all viruses of 100%, which indicated negative detection in the treated water.

Adsorptive removal of eriochrome black T (EBT) dye by using surface active low cost zinc oxide nanoparticles: A comparative overview

The ecological toxicity imparted by non-biodegradable organic dyes has been considered as a major risk to handle in front of mankind. In this view, the low-cost zinc oxide nanoparticles (ZnO-NPs) were facially synthesized by coating the surface with surfactant (CTAB) and ionic liquid (BMTF) molecules for the effective removal of Eriochrome Black T (EBT) from aqueous media. Various advanced characterization techniques have given insight into the morphological features, crystalline structure and physio-chemical properties of as-synthesized ZnO-NPs. The systematic analysis of the adsorption isotherms and kinetics models specifies that the adsorption of EBT follow Freundlich model and pseudo-second-order kinetics. The intraparticle diffusion model displayed a linear relationship (R2 = 0.98, 0.97 and 0.94 for BMTF@ZnO, CTAB@ZnO and bare ZnO-NPs), which shows that pore diffusion rate is affected by surface modification and effects the overall EBT adsorption process. Furthermore, after the removal of 87% and 84% of EBT dye by BMTF@ZnO-NPs and CTAB@ZnO-NPs, the fabricated nanoadsorbents of ZnO were successfully regenerated and reused after the treatments up to four times. The adsorption aptitude of ZnO-NPs towards EBT dye was systematically explored in real wastewater samples and interference study of inorganic metallic salts was also performed. The toxicity estimations of the treated dye solutions were made using floral and fungal activities, to ascertain their non-toxic nature before releasing into the environment. These outcomes have supported the immense potential of ZnO-NPs towards the removal of EBT in a cost effective manner.

Application of chemometrics for modeling and optimization of ultrasound-assisted dispersive liquid\u2013liquid microextraction for the simultaneous determination of dyes

As the world population continues to grow, so does the pollution of water resources. It is, therefore, important to identify ways of reducing pollution as part of our effort to significantly increase the supply of clean and safer water. In this study, the efficiency of ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) as a fast, economical, and simple method for extraction malachite green (MG) and rhodamine B (RB) dyes from water samples is investigated. In optimal conditions, the linear dynamic range (LDR) for RB and MG is 7.5–1500 ng mL−1 and 12–1000 ng mL−1, respectively. The limit of detection (LOD) is 1.45 ng mL−1 and 2.73 ng mL−1, and limit of quantification (LOQ) is 4.83 ng mL−1 and 9.10 ng mL−1 for RB and MG, respectively. Extraction efficiency is obtained in the range of 95.53–99.60%. The relative standard deviations (RSD) in real water and wastewater samples are less than 3.5. The developed method is used successfully in the determination of RB and MG dyes from water samples and there are satisfactory results.