Adsorption Of DCF Research Articles

Adsorption behavior of diclofenac-containing wastewater on three kinds of sewage sludge.

Diclofenac (DCF) is one of the most frequently detected non-steroidal anti-inflammatory drugs (NSAIDs) in the water environment. One of the main removal routes of DCF in wastewater is sludge adsorption, and the mechanisms need to be investigated. In this study, the effects of adsorption time, temperature, pH value, and ionic strength on the adsorption of DCF on suspended particles (SP), secondary sedimentation tank sludge (SSTS) and concentrated sludge (CS) were investigated. The results showed that most of the adsorption of DCF by the three matrices was conducted in the first 4 h and equilibrium was achieved at 8 h. The adsorption kinetics were well fitted with the pseudo-second-order model and the rate constants were 0.29-0.88 mg·(μg·min)-1, with chemical adsorption as the dominant one. Adsorption isotherm conformed to Freundlich, Langmuir and Linear adsorption isotherm models. The order of adsorption capacity was: CS > SSTS > SP, which was proportional to the organic matter content and specific surface area of the adsorbents. The decrease of the pH value and the increase of ionic strength promoted the adsorption of DCF. The results can provide data support for the removal of DCF from different treatment unit types in wastewater treatment plants.

Mechanistic insight into the adsorption of diclofenac by MIL-100: Experiments and theoretical calculations

The development of high-efficiency adsorbents and the exploration of their adsorption mechanisms are major challenges in environmental remediation. Herein, MIL-100 was prepared, characterized, and utilized for the adsorptive removal of diclofenac sodium (DCF) from aqueous solutions. A high monolayer adsorption capacity of 773 mg g−1 was recorded. The adsorption mechanism was proposed based on different contributions of two types of pore structure of MIL-100 to the adsorption of DCF from aqueous solutions according to the experimental results and theoretical calculation. During adsorption process, DCF (5.2 × 7.4 × 10.3 Å) diffused through the free area of hexagonal pores (8.6 × 8.6 Å) into the cages of MIL-100, whilst it was adsorbed by the pentagonal pores (4.8 × 5.8 Å) preferentially. Internal mass transfer resistance, which was identified as one of the dominant rate-limiting steps by the mass transfer resistance kinetic models based on the Sips model, will be derived from the diffusion process, which was affected by the size-sieving effect of the pore structure of MIL-100. The successful diffusion of DCF into the interior of MIL-100 and the stable configuration between MIL-100 and DCF accounted for the high adsorption capacity. The capture of DCF into MIL-100 also resulted in the pore size distribution variation of adsorbent, which provided vital experimental evidence for the proposed mechanism. This study may offer deeper insights into other pollutants removal by metal-organic frameworks type adsorbents.

Preparation, characterization of titanate nanosheet–pozzolan nanocomposite and its use as an adsorbent for removal of diclofenac from simulated hospital effluents

Abstract The nanocomposite titanate nanosheet–pozzolan (TNS–PZ) was prepared by the alkaline hydrothermal process using titanium (IV) isopropoxide solution as titanium precursors at different concentrations. The characterization of the material was obtained by, Diffuse Reflectance UV–vis analysis (DRUV), X-ray diffraction (XRD), Energy-dispersive X-Ray spectroscopy, Fourier transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption/desorption isotherms. The adsorbent material was used for successful removal of the anti-inflammatory diclofenac (DFC) from aqueous solutions. The kinetic data were better fitted to nonlinear general order kinetic model, based on the Bayesian Information Criterion (BIC). The equilibrium isotherms also were obtained employing the nonlinear method and based on the BIC; the best isotherm model was the Liu. Based on the Liu isotherm model, the maximum sorption capacity (Qmax) of DCF onto the TNS–PZ adsorbent was 90.52 mg g−1 at 10 °C. The thermodynamic parameters of adsorption were calculated, and the adsorption process was spontaneous, exothermic, and the magnitude of changes in enthalpy, are consistent with physical adsorption of DCF onto TNS–PZ. Also, the adsorbent was tested for simulated hospital effluents, and it was able to remove up to 96.50% of the effluents.

Fast removal of diclofenac sodium from aqueous solution using sugar cane bagasse-derived activated carbon

The production of high quality activated carbon from inexpensive, abundant and sustainable feedstocks such as agro-waste materials with improved adsorption capacity towards pharmaceuticals and personal care products (PPCPs) in wastewater has lately become one of the principal focuses in the environmental research. Herein, porous activated carbon (SCB-AC) has been produced from sugar cane bagasse, one of the most prevalent agro-waste materials in Egypt, through a facile single-step ZnCl2 activation and then used for the adsorptive removal of diclofenac sodium (DFC), as a representative PPCP, out of aqueous solution. Techniques such as XRD, Raman spectroscopy, N2 adsorption-desorption measurements, FTIR, SEM and HRTEM have been conducted to study the structural characteristics and the surface chemistry of the synthesized SCB-AC. SCB-AC not only exhibited fast adsorption rate and high binding capacity towards DFC but also remarkable recyclability via simple washing of the DFC-saturated adsorbent with acetone. The equilibrium and kinetics aspects of DFC adsorption onto SCB-AC were explored and implied the aptness of the Langmuir and the pseudo-second-order kinetic models for interpreting the adsorption of DFC onto SCB-AC. Additionally, the influence of pH on the adsorbent surface charge and DCF adsorption capacity was investigated to reveal the presumable mechanism underlying the current adsorption process. All the results demonstrated that SCB-AC is a brilliant adsorbent for the effectual removal of PPCPs from contaminated effluents.

Recyclable Fully Biobased Chitosan Adsorbents Spray-Dried in One Pot to Microscopic Size and Enhanced Adsorption Capacity.

A facile one-pot spray-drying process was developed for fabrication and in situ crosslinking of chitosan microspheres to improve the adsorption capacity by microscopic design. A fully biobased nature was achieved by utilizing genipin (GP) as a crosslinking agent and chitosan-derived nanographene oxide (nGO) as a property tuner. The produced chitosan microspheres were further proven as powerful adsorbents for common wastewater contaminants such as anionic dyes and pharmaceutical contaminants, here modeled by methyl orange (MO) and diclofenac sodium (DCF). By regulating the amount of GP and nGO, as well as by controlling the process parameters including the spray-drying inlet temperature and postheat treatment, the surface morphology, size, zeta potential, and adsorption efficiency of the microspheres could be tuned accordingly. The adsorption efficiency for MO and DCF reached 98.9 and 100%, respectively. The microspheres retained high DCF adsorption efficiency after six adsorption and desorption cycles, and the recyclability was improved by the incorporated nGO. The fabricated microspheres, thus, have great potential as reusable and eco-friendly adsorbents.

Highly efficient removal of diclofenac sodium from medical wastewater by Mg/Al layered double hydroxide-poly(m-phenylenediamine) composite

The emerging pollutant non-steroidal diclofenac sodium (DCF) has aroused increasing concerns, and the efficient removal of DCF from wastewater is becoming an urgent problem. In this study, the Mg/Al layered double hydroxide-Poly(m-Phenylenediamine) (LDH-PmPD) composite was synthesized, characterized and used for DCF adsorptive removal. The adsorption kinetics, isotherms as well as various influence factors, e.g., pH, humic acid, ions species and strength on the DCF removal were systematically investigated. The results showed that the presence of LDH weakened the accumulating density of PmPD and increased the specific surface area, which favored DCF adsorption on LDH-PmPD surface. LDH-PmPD exhibited a maximum adsorption capacity of 588 mg/g, which was superior to those of the conventional adsorbents. The artificial aging (100 d) experiment indicates a good stability of LDH-PmPD. Furthermore, due to the presence of electrostatic attraction, π-π electron-donor-acceptor interaction and N···HO hydrogen bonding between DCF and LDH-PmPD, the adsorption process was very effective in medical wastewater. The DCF removal efficiency reached nearly 100% within only 2 min in real medical wastewater using 0.125 g/L adsorbent. All these suggested that the prepared LDH-PmPD has great potential for DCF-contaminated water treatment.

A porous polyaniline nanotube sorbent for solid-phase extraction of the fluorescent reaction product of reactive oxygen species in cells, and its determination by HPLC.

A method is described for extracting and detecting the fluorescent reaction product (2',7'-dichlorofluorescein, DCF) that is formed by reaction of reactive oxygen species (ROS) with dichlorodihydrofluorescein diacetate (DCFH-DA). DCF is extracted by using porous polyaniline nanotubes (PPN) which have a large specific surface and pore volume which favor the adsorption capacity. Additional attractive features include an appropriate pore size distribution, hydrophobic surface, and electron-attracting groups which contribute to DCF adsorption. A variety of methods was applied to characterize the morphology of PPN. Under optimal conditions and by performing DCF in 0.08-1.0μM concentrations, the correlation coefficient of the calibration plot is 0.999. The limits of detection for standard DCF solutions is 20nM. Compared with commercial sorbents for solid-phase extraction (SPE) such as commercially available carbon or Welchrom® C18, the use of the new sorbent results in better retraction recovery (92%) and longer reuse times (30 times). Doxorubicin and X-ray radiation were used to externally stimulate the ROS production in HepG2 and Hela cells. ROS was stabled by DCFH-DA and quantified by DCF. Following SPE, DCF was detected by HPLC and the concentration ROS was calculated. Graphical abstract ᅟ.

Tunable chitosan hydrogels for adsorption: Property control by biobased modifiers

A sustainable strategy to fabricate chitosan-based composite hydrogels with tunable properties and controllable adsorption capacity of trace pharmaceuticals was demonstrated. Two biobased modifiers were utilized to tune the properties, nano-graphene oxide (nGO) derived from chitosan via microwave-assisted carbonization and oxidation, and genipin as the crosslinking agent. An increase in genipin content facilitated an increase in the degree of crosslinking as shown by improved storage modulus and decreased swelling ratio. Increasing nGO content changed the surface microtopography of the hydrogel which correlated with the surface wettability. nGO also catalyzed the genipin-crosslinking reaction. The hydrogel was further shown to be an effective adsorbent for a common anti-inflammatory drug, diclofenac sodium (DCF), with the removal efficiency ranging from 91 to 100% after 48 h. DCF adsorption efficiency could be tuned through simple alteration of nGO and genipin concentration, which provides promising potential for this environmental-friendly adsorbent in removal of DCF from pharmaceutical waste water.

Efficient adsorption and removal of diclofenac sodium from water with quaternary ammonium functionalized metal-organic frameworks

A quaternary ammonium functionalized MIL-101(Cr) named MIL-101(Cr)-NMe3 was synthesized and explored as a novel adsorbent for the fast removal of diclofenac sodium (DCF) in water. The adsorption process of kinetics, adsorption isotherms, thermodynamics, and adsorbent regeneration were investigated. And the effects of key parameters such as pH value and ionic strength on the adsorption of DCF were also studied. The results showed that the adsorption of DCF on MIL-101(Cr)-NMe3 was very fast. Most of DCF were adsorbed in the first 30 min. The adsorption kinetics of DCF on MIL-101(Cr)-NMe3 obeyed pseudo-second-order kinetics. The adsorption isotherms of DCF on MIL-101(Cr)-NMe3 fitted well to the Langmuir adsorption model. And the maximum adsorption capacity was 310.6 mg/g at 20℃. The analysis of the adsorption mechanism showed that the electrostatic interaction and π-π stacking interaction between DCF and MIL-101(Cr)-NMe3 were responsible for the efficient adsorption. Regeneration experiments indicated that the used MIL-101(Cr)-NMe3 was recycled at least five times without significant loss of adsorption capacity. The fast adsorption kinetics, high adsorption capacity, and excellent reusability made MIL-101(Cr)-NMe3 attractive for removal DCF from aqueous solution.

Mycoremediation of diclofenac using Mucor hiemalis

ABSTRACTDiclofenac (DCF) is a pharmaceutical drug widely found in the aquatic environment, where it represents a persistent, anthropogenic hazard to all biota. Owing to the reported inefficiency of water treatment strategies to remove pharmaceuticals, the present study aimed to investigate the ability of the aquatic fungus Mucor hiemalis to take up and accumulate DCF. Cultures of M. hiemalis were exposed to varying concentrations of DCF (10, 25 and 50 µg/L) over a period of 144 h. In the presence of M. hiemalis, DCF concentrations in the media decreased by 95% within 24 h. This early removal was most likely due to extracellular metabolism of DCF, as low proportions of the pharmaceutical were found in the mycelium of the fungus, thereby excluding bioaccumulation as the main mode of removal. However, adsorption of DCF onto the surface of the M. hiemalis pellets cannot be excluded. Our study provides the first report of DCF remediation using M. hiemalis and is the first successful step towards a feasible and inexpensive bioremediation technique for DCF.

Adsorption of diclofenac sodium from water using oxidized activated carbon

Adsorption of diclofenac sodium (DCF) from aqueous solutions using surface-modified/oxidized activated carbons (OACs) was investigated and compared with that over virgin activated carbon (AC). The obtained results showed a remarkable increase (∼6 times) in DCF removal over oxidized AC compared to that over a commercial, unmodified AC, despite the decreased surface area in the OAC. The large increase in DCF removal may be due to the presence of acidic surface functional groups, which are created on the AC surface upon oxidation. To understand the role of these acidic functional groups on the increased adsorption capacity (qt), the concentration of acidic groups was determined using Boehm titration after oxidation with different quantities of oxidizing agent. The adsorption capacity of the OAC prepared by treatment with 2.0M ammonium persulfate solution (OAC (2.0)) was the highest of the prepared adsorbents. Therefore, OAC (2.0) was studied in detail by characterizing the material and investigating the adsorption performances. The effect of pH on the surface charge (zeta potential) and DCF adsorption capacity of OAC (2.0) was investigated to lead to the mechanism of DCF adsorption such as hydrogen bonding and electrostatic interactions. Additionally, the OAC can be recycled for adsorptive removal of DCF by simple solvent washing. Therefore, the OAC was found to be a promising adsorbent for the removal of DCF from contaminated water.

Removal of diclofenac sodium from aqueous solution by Isabel grape bagasse

The aim of the present work was to evaluate the morphologic and chemical characteristics of Isabel grape (Vitis labrusca×Vitis vinifera) bagasse and to describe the adsorption of diclofenac sodium (DCF) from aqueous solutions by this biomass. Grape bagasse constituted mainly of particles with heterogeneous shapes and sizes, and it exhibited a macroporous structure and a low specific surface area (∼2m2g−1). The adsorbent material was also rich in oxygenated functional groups, especially –OH, and required an acidic pH to neutralize its surface. With respect to the adsorption of DCF, the percentage removal did not appear to depend on the initial concentration of the pharmaceutical. A pseudo-second-order kinetic model described the rate-controlling step, and the adsorption isotherms were well fitted by the Freundlich model. Concerning the thermodynamic data, the results showed that the adsorption of DCF onto grape bagasse occurred via an exothermic process accompanied by a decrease in the randomness at the solid/solution interface. Furthermore, the removal percentages of DCF ranged from 16.4% to 22.8%.