Adsorption Of Diethyl Phthalate Research Articles

Use of Typical Wastes as Biochars in Removing Diethyl Phthalate (Det) from Water

Diethyl phthalate (DEP), one of the six typical PAEs priority pollutants declared by the US EPA, has attracted tremendous attention due to its widespread pollution and was selected as the adsorbate in this study. Properties of biochar samples obtained from three different feedstocks, i.e., sawdust (SDBC), rice straw (RSBC), and giant reed (GRBC), pyrolyzed at 400 °C as well as their ability to adsorb DEP from an aqueous solution were investigated. The results showed that the adsorption kinetics were well fitted with the pseudo-second-order model (R2 > 0.99) and the intraparticle diffusion model (R2 > 0.98). The maximal adsorption capacity of the DEP by the prepared biochar was in an order of GRBC (46.04 mg g−1) > RSBC (31.54 mg g−1) > and SDBC (18.39 mg g−1). The higher adsorption capacity of DEP by GRBC is mainly attributed to the higher surface area. The reduction in adsorption capacity of the biochar against DEP with an increase in the solution pH (from 2.5 to 10.0) was possibly due to promoting the electrostatic repulsion between the DEP and the surface of the biochar. However, the increasing sodium ionic strength promoted the adsorption of the biochar, which could be interpreted by the reduced solubility of the DEP due to enhancing “salting out” effects as increasing sodium concentration. In addition, it was favorable for the adsorption of DEP onto the biochars at a lower temperature (15 °C) and the calculated ∆G0 was less than zero, indicating that the adsorption was a spontaneous and exothermic process. These experiments designate that these derived biochars can be used as an inexpensive adsorbent for the purification of PAEs contaminated water.

Mg-Al–layered Double Hydroxide as Promising Sustainable Nanoadsorbent for Application in Water/Wastewater Treatment Processes; Diethyl Phthalate Removal

Introduction: Since phthalate esters and their derivatives have the potential to disrupt proper endocrine function, these compounds are considered as one of the most important groups of endocrine-disrupting chemicals. The presence of these compounds in various aquatic environments has caused main concerns about human and animal health and causes problems in the environment. Materials and Methods: The treatment process was carried out in a glass reactor containing 200 mL polluted water at room temperature. The Mg-Al layered double hydroxides (Mg-Al-LDH) were successfully synthesized and were applied as adsorbents for the removal of Diethyl Phthalate (DEP) from polluted water. The kinetics and isotherm of the process were investigated to determine the exact mechanism of DEP removal from the water medium. Results: The Mg-Al-LDH was a surface area of 673 (m2 g-1), a total pore of 0.716 (cm3 g-1), and microspore volumes of 0.627 (cm3 g-1), and a pore diameter of 8.64 nm. The maximum DEP removal efficiency of 96.7% was obtained at the DEP concentration of 10 mg L-1, Mg-Al-LDH dosage of 0.50 g L-1, and the reaction time of 30 min. The second-order kinetic model well depicted the kinetics of DEP adsorption (R2 = 0. 99). The Langmuir isotherm model best described the data by predicting the maximum adsorption capacity (qm) of 95.6 mg g-1 and R2 of 0.99. Conclusion: All the results demonstrate that the Mg-Al-LDH is an efficient, safe, and efficient adsorbent in water and wastewater treatment.

Mechanism of accurate recognition and catalysis of diethyl phthalate (DEP) in wastewater by novel MIL100 molecularly imprinted materials

In this study, MIL100(Fe-base metal organic framework) molecularly imprinted catalyst(MIL100-MIP) was synthesized using the surface imprinting method. Results determining the pore structures as well as the kinetic and thermodynamic properties of MIL100-MIP showed that the recognition process of imprinted materials containing DEP occurred on the outer surface. By regulating the thickness of the imprinted layer to optimize persulfate(PS) transfer, the transfer efficiency of PS and the rate constant(K) of MIL100-MIP were four times higher than that of MIL100. With the synergy of adsorption and catalysis, the removal of DEP from MIL100-MIP reached 105.2 mg g−1. The precise adsorption of DEP was mainly realized by hydrogen bonding, electrostatic forces and hydrophobic interactions of π-π stacking. The enhanced DEP concentration on the surface improves the contact efficiency between the sulfate radicals and the pollutants, thereby promoting its catalytic performance. Such molecularly imprinted catalysis materials have an enormous potential for waste water treatment.

One-step controlled electrodeposition of iron-based binary metal organic nanocomposite

A cauliflower-shaped Fe/Fe-BTC nanocomposite was prepared by one-step controlled cathodic electrodeposition method. The obtained Fe-BTC nanoscale film was characterized by scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT-IR), thermogravimetric analysis (TGA) and electrochemical measurements, indicating its morphology, structure and electrochemical activities varied with the applied cathodic potential. The electrodeposition process was investigated thoroughly and the electrosynthesis mechanism of the Fe/Fe-BTC nanocomposite was proposed. The Fe/Fe-BTC nanoscale film deposited at −1.5 V exhibited the loosest morphology and best electrochemical activity, which showed the best application potential in electrocatalytic H2O2 reduction and adsorption of diethyl phthalate (DEP) and dibutyl phthalate (DBP). The iron-based binary metal organic materials were designable and could be applied in the field of electrocatalysis and extraction.

Rapid and efficient ultrasonic assisted adsorption of diethyl phthalate onto FeIIFe2IIIO4@GO: ANN-GA and RSM-DF modeling, isotherm, kinetic and mechanism study

Herein, an ultrasonic assisted dispersive magnetic solid-phase adsorption method along with a high-performance liquid chromatography system for the diethyl phthalate (DEP) removal was developed. In this regard, magnetic iron oxide/graphene oxide (MGO) nanocomposites were prepared by a simple and effective chemical co-precipitation method, followed by nucleation and growth of nanoparticles. The structure and morphology of MGO was identified by Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) spectroscopy X-ray diffraction (XRD), Vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption techniques. The interactive and main effect of parameters such as pH, adsorbent dosage, sonication time and concentration of DEP involved in the adsorption process were set within the ranges 3.0–11.0, 0.10–0.50 g L−1, 1–5 min, 5–10 mg/L, respectively. Root means square error (RMSE), mean absolute error (MAE), absolute average deviation (AAD), and coefficient of determination (R2) was employed to examine the applicability of the response surface methodology (RSM) and artificial neural network (ANN) models for the description of experimental data. Compared to RSM, the ANN showed a more accurate performance for modeling the process of DEP adsorption. Using genetic algorithm-ANN, optimum conditions were set to 5.38, 334.7 mg/L, 3.723 min and 4.21 mg/L for pH, adsorbent dose, sonication time and concentration of DEP, respectively. Under the optimized conditions, the maximum adsorption capacity and adsorption factors were 116.933 mg/g and 100%, respectively, while the relative standard deviations (RSDs) was <1.6% (N = 5). The isotherm models display that the Langmuir has the best fit with the equilibrium data, and adsorption kinetics followed the pseudo-second-order model. The thermodynamic results confirmed that the sorption was endothermic and occurred spontaneously. The results exhibited that MGO has excellent potential as an adsorbent for the removal of phthalates from the contaminated water.

Insight into mechanism of aged biochar for adsorption of PAEs: Reciprocal effects of ageing and coexisting Cd2+

Biomass derived biochar is a stable carbon-rich product with potential for soil amendment. Introduced into the natural environment, biochar will naturally experience ‘ageing’ processes that are liable to change its physicochemical properties and the mobility of sorbed pollutants over the longer term. To elucidate the reciprocal effects of biochar ageing and heavy metal adsorption on the affinity of biochar for organic pollutants, we systematically assessed the adsorption of diethyl phthalate (DEP), representative of phthalic acid esters (PAEs), to fresh and aged biochars with and without coexistence of Cd2+. Long-term oxidative ageing was simulated using 5% H2O2 and applied to biochar samples made from corn cob, maize straw and wheat straw made by pyrolysis at both 450 °C and 650 °C. Our results showed that biochar made at lower temperature (450 °C) and from straw exhibited the higher adsorption capacity, owing to their greater polarity and abundance of O-containing functional groups. The adsorption of DEP onto fresh biochars was found to be driven by van der Waals force and H-bonding. Biochar made at the higher temperature (650 °C) displayed higher carbon stability than that produced at lower pyrolysis temperature. Oxidized biochar showed lower adsorption capacity than fresh biochar owing to the formation of three-dimensional water clusters on biochar surface, which blocked accessible sites and decreased the H-bonding effect between DEP and biochars. The coexistence of Cd2+ suppressed the sorption of DEP, via competition for the same electron-rich sites. This indicates that cation/π-π EDA interactions are the primary mechanism for PAE and Cd2+ stabilization on biochar. Our study sheds light on the mechanism of organic pollutant sorption by biochar, as well as the potential susceptibilities of this sorption to ageing effects in the natural environment.

Removal of diethyl phthalate via adsorption on mineral rich waste coal modified with chitosan

Phthalic acid esters or phthalates in wastewater are priority pollutants and demand efficient method for remediation. Here we present a novel utilization of low grade coal, which is otherwise a waste, modified by chitosan as adsorbent for removal of diethyl phthalate (DEP) via adsorption. A low carbon and high silicate content coal was chosen, characterized by CHN analyzer, energy dispersive X-ray analysis and by X-ray diffraction. A composite of mineral rich coal and chitosan is prepared via electrostatic interaction and hydrogen bonding between the hydroxyl groups of chitosan and the silicate group of coal; confirmed by Fourier transformed infrared spectroscopy, thermogravimetry analysis and zeta potential measurements. An optimized 9:1 weight ratio of coal-chitosan composite exhibited a positive zeta potential value in aqueous medium and corresponded to 91.1% DEP adsorption at an optimized condition e.g., pH5.8, adsorbent dose of 4mg/mL and contact time of 4h. The adsorption is thermodynamically favorable and followed pseudo-second order kinetics, and attributable to chemisorption process, is attributed to electrostatic interaction and hydrogen bonding between the DEP and the functional groups in the composite. The adsorption isotherm data was best fitted non-linearly by Sips isotherm model, which is consistent with Freundlich adsorption isotherm for lower concentration of DEP (5 to 100mg/L), while Langmuir adsorption was favored for adsorption of higher DEP concentrations (100 to 400mg/L). The qmax was 42.67mg/g, which is a significant improvement in DEP sorption from aqueous medium among the readily degradable adsorbents reported so far. The practical application of coal-chitosan composite as adsorbent has been demonstrated by its re-usability and ability for sorption of DEP from spiked municipal wastewater, supported by decrease in chemical oxygen demand value of treated wastewater.

Diethyl phthalate Determination in workplace air

Diethyl phthalate (DEP) is an ester of phthalic acid and an ethanol. It is a colorless, oily liquid. This substance is used in industry as a solvent for cellulose acetate and nitrocellulose, and a plasticizer of plastics. It is added to nail polish, perfumes in cosmetics and detergents, food packaging and pharmaceuticals. Diethyl phthalate is a substance which is toxic if inhaled, irritating to eyes and skin, toxic for reproduction (it is suspected that acts harmful to fertility or unborn child). The aim of this study was to develop and validate a method for determining concentrations of diethyl phthalate in workplace air in the range from 1/10 to 2 MAC values in accordance with the requirements of Standard No. PN-EN 482. The study was performed using a gas chromatograph (GC) with a flame ionization detector (FID) with a capillary column HP-INNOWAX (60 m × 0.25 mm, 0.15 µm). The method is based on the adsorption of diethyl phthalate on glass microfiber filter, desorption of analysed compound with ethanol and analysis of the resulting solution with GC-FID. The average desorption efficiency of diethyl phthalate from filter was 90%. Application of column HP-INNOWAX enables selective determination of diethyl phthalate in the presence of other solvents. The measurement range was 0.3  6 mg/m3 for a 240-L air sample. The limit of detection (LOD) and the limit of quantification (LOQ) are 0.09 µg/ml and 0.27 µg/ml, respectively. The analytical method described in this paper enables selective determination of inhalable fraction of diethyl phthalate in workplace air in the presence of other substances at concentrations from 0.3 mg/m3 (1/10 MAC value). The method is precise, accurate and it meets the criteria for procedures for measuring chemical agents listed in Standard No. EN 482. The method can be used for assessing occupational exposure to diethyl phthalate and associated risk to workers’ health. The developed method of determining diethyl phthalate has been recorded as an analytical procedure (see appendix).

Adsorption and removal of diethyl phthalate from aqueous media with poly(hydroxyethyl methacrylate) nanobeads

In this study, poly (hydroxyethyl methacrylate) (PHEMA) nanobeads with an average size of 115nm were prepared by emulsion polymerization. The nanobeads were characterized with infrared spectroscopy, scanning electron microscopy, and zeta size analysis. The surface area of the PHEMA nanobeads was calculated as 541.4 m2/g. Then, diethyl phthalate (DEP) removal efficiency of the PHEMA nanobeads from aqueous media was investigated. At a fixed adsorbent/solution ratio, various factors affecting the adsorption of DEP from aqueous solution such as pH, initial concentration, contact time, temperature, and adsorbent dosage were analyzed. The maximum DEP adsorption capacity of the PHEMA nanobeads was determined as 265.1 mg/g at pH 4.0, 25°C. The Sips isotherm model fits the experimental data in the wide range of DEP concentration tested (1–300 mg/L). The pseudo-first-order, pseudo-second-order, modified Ritchie’s-second-order kinetic models were used to test the adsorption kinetics. The DEP adsorption capacity of the nanobeads did not change after five batch successive usages. DEP removal efficiency of the PHEMA nanobeads from different water media such as saliva, sweat, and tap water was also evaluated. The removal efficiencies in the range from 82.4 to 100.0% demonstrate the usability of PHEMA nanobeads for DEP removal from real samples.

Effect of aging process on adsorption of diethyl phthalate in soils amended with bamboo biochar

Biochar is a carbonaceous sorbent and can be used as a potential material to reduce the bioavailability of organic pollutants in contaminated soils. In the present study, the adsorption and desorption of diethyl phthalate (DEP) onto soils amended with bamboo biochar was investigated with a special focus on the effect of biochar application rates and aging conditions on the adsorption capacity of the soils. Biochar amendment significantly enhanced the soil adsorption of DEP that increased with increasing application rates of biochar. However, the adsorption capacity decreased by two aging processes (alternating wet and dry, and constantly moist). In the soil with low organic carbon (OC) content, the addition of 0.5% biochar (without aging) increased the adsorption by nearly 98 times compared to the control, and exhibited the highest adsorption capacity among all the treatments. In the soil with high OC content, the adsorption capacity in the treatment of 0.5% biochar without aging was 3.5 and 3 times greater than those of the treatments of biochar aged by alternating wet and dry, and constantly moist, respectively. Moreover, constantly moist resulted in a greater adsorption capacity than alternating wet and dry treatments regardless of biochar addition. This study revealed that biochar application enhanced soil sorption of DEP, however, the enhancement of the adsorption capacity was dependent on the soil organic carbon levels, and aging processes of biochar.

Diethyl phthalate removal from aqueous phase using poly(EGDMA-MATrp) beads: kinetic, isothermal and thermodynamic studies

In this study, poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [poly(EGDMA-MATrp)] beads (average diameter = 106–300 µm), which were synthesized by co-polymerizing of N-methacryloyl-l-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA), were used for diethyl phthalate (DEP) adsorption. The various factors affecting the adsorption of DEP from aqueous solutions such as pH, initial concentration, contact time and temperature were analysed. Adsorption behaviour of DEP on the poly(EGDMA-MATrp) beads was investigated by varying pH values of solution, contact time, initial concentration and temperature. An optimum adsorption capacity of 590.7 mg/g for DEP was obtained at 25 °C. The present adsorption process obeyed a pseudo-second-order kinetic model. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. Thermodynamic parameters ΔH = 7.745 kJ/mol, ΔS = 81.92 J/K/mol and ΔG = −16.69 kJ/mol to −18.31 kJ/mol with the rise in temperature from 25 °C to 45 °C indicated that the adsorption process was endothermic and spontaneous.

Adsorption of Diethyl Phthalate on Carbon Nanotubes: pH Dependence and Thermodynamics

Abstract The adsorption mechanism of diethyl phthalate (DEP) on solid particles is still unclear due to the complicated properties of adsorbents. Carbon nanotubes (CNTs) have definite structures and uniform surfaces, thus they were chosen as the model adsorbents in this study. The site energy distribution may provide important information for adsorption mechanisms, but no study has applied site energy distribution to illuminate the DEP thermodynamic adsorption on CNTs. Thus, this study focused on the thermodynamic adsorption behavior of DEP on CNTs combining the site sorption energy distribution analysis. The adsorption coefficient Kd followed the order: MG>MH≈MC. Surface area was not the only factor for DEP adsorption on CNTs. Hydrophobic interactions, H-bonds, morphology of CNTs, and DEP molecule structure may control DEP adsorption. Electron donor-acceptor interaction was limited in this system. The thermodynamic parameters changes showed that the adsorption process is exothermic and spontaneous. The s...

Removal of diethyl phthalate from aqueous phase using magnetic poly(EGDMA–VP) beads

The barium hexaferrite (BaFe12O19) containing magnetic poly(ethylene glycol dimethacrylate–vinyl pyridine), (mag-poly(EGDMA–VP)) beads (average diameter=53–212μm) were synthesized and characterized. Their use as an adsorbent in the removal of diethyl phthalate (DEP) from an aqueous solution was investigated. The mag-poly(EGDMA–VP) beads were prepared by copolymerizing of 4-vinyl pyridine (VP) with ethylene glycol dimethacrylate (EGDMA). The mag-poly(EGDMA–VP) beads were characterized by N2 adsorption/desorption isotherms (BET), vibrating sample magnetometer (VSM), X-ray powder diffraction (XRD), elemental analysis, scanning electron microscope (SEM) and swelling studies. At a fixed solid/solution ratio, the various factors affecting the adsorption of DEP from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. The maximum DEP adsorption capacity of the mag-poly(EGDMA–VP) beads was determined as 98.9mg/g at pH 3.0, 25°C. All the isotherm data can be fitted with both the Langmuir and the Dubinin-Radushkevich isotherm models. The pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models were used to describe the adsorption kinetics. The thermodynamic parameters obtained indicated the exothermic nature of the adsorption. The DEP adsorption capacity did not change after 10 batch successive reactions, demonstrating the usefulness of the magnetic beads in applications.

Removal of Diethyl Phthalate from Aqueous Media by Adsorption on Different Activated Carbons: Kinetic and Isotherm Studies

The adsorption of diethyl phthalate (DEP) was studied on four activated carbons (ACs) with different chemical and microporous properties. The kinetic results showed that the non-linear form of the pseudo-second order kinetic model provided the best parameters. Results further showed that the DEP adsorption kinetics is favored by ACs which have a ratio of a specific microporous surface to a specific external surface that is relatively low. Besides, an increase in temperature induced an increase in the rate constant k 2 , but the adsorption capacity is temperature independent. Two models, (Langmuir (linear and non-linear forms) and Dubinin-Radushkevich-Kaganer (DRK)), were tested from experimental data. While the Langmuir model provided the best correlation on all the ACs studied. The surface occupied, calculated with the Langmuir parameter obtained by the non-linear form, evidenced the importance of the external surface and the mean pore size. The results show that the non-electrostatic interactions are predominant in the DEP adsorption and are essentially due to dispersion and hydrophobic interactions (for L27 and X17). In the case of F22 and S21 the DEP adsorption is only due to dispersion interaction. A comparison of the thermogravimetric analysis of the ACs washed and saturated shows that the DEP is totally desorbed between 300 and 500°C with a characteristic peak.

Influence of Gas Velocity and Humidity on Diethyl Phthalate Adsorption and Desorption on Silicon Surface

The real-time adsorption and desorption of water and diethyl phthalate on silicon surface were studied using a quartz crystal microbalance in ambient nitrogen, having various values of humidity, gas velocity and diethyl phthalate concentration. In a steady state, the adsorbed amount of water and diethyl phthalate is considered to depend only on each concentration in the ambient nitrogen. However, in a non-steady state state, the gas velocity at the quartz crystal microbalance enhances both the adsorption rate and the desorption rate. Therefore, the gas velocity at the measurement point is concluded to be one of the key parameters that influence the organic contamination measurement.

Influence of Gas Velocity and Humidity on Diethyl Phthalate Adsorption and Desorption on Silicon Surface

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