Showing papers on "Langmuir published in 2012"
15 Feb 2012
TL;DR: Graphene oxide is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution and has a better rate constant of sorption, 0.065 g mg(-1) h(-1), than other adsorbents.
Abstract: Significant concerns have been raised over pollution of antibiotics including tetracyclines in aquatic environments in recent years. Graphene oxide (GO) is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution. Tetracycline strongly deposited on the GO surface via π-π interaction and cation-π bonding. The adsorption isotherm fits Langmuir and Temkin models well, and the theoretical maximum of adsorption capacity calculated by Langmuir model is 313 mg g(-1), which is approximately in a close agreement with the measured data. The kinetics of adsorption fits pseudo-second-order model perfectly, and it has a better rate constant of sorption (k), 0.065 g mg(-1) h(-1), than other adsorbents. The adsorption capacities of tetracycline on GO decreased with the increase in pH or Na(+) concentration. The adsorption isotherms of oxytetracycline and doxycycline on GO were discussed and compared.
1,164 citations
TL;DR: In this article, a single-stage batch absorber design for the Congo red adsorption onto pine cone biomass was presented based on the Freundlich isotherm model equation.
704 citations
TL;DR: In this article, the effects of pH, contact time, initial concentration of adsorbate and temperature on adsorption of activated carbon were investigated, and the results showed that both Langmuir and Freundlich models fitted the data reasonably but the Langmuirusorption isotherm model fitted better in the temperature range studied.
609 citations
TL;DR: A novel magnetic composite bioadsorbent composed of magnetic chitosan and graphene oxide (MCGO) was prepared as the magnetic adsorbent, indicating that the adsorption was spontaneous, favorable and exothermic process in nature.
570 citations
TL;DR: In this article, the effects of several experimental parameters have been investigated using the batch adsorption technique at different temperature and modelled with the Langmuir and Freundlich isotherms.
548 citations
TL;DR: In this article, a new synthesis was developed to create highly porous nanocomposite material consisting of MgO nano-flakes within a biochar matrix that has high sorption ability for ionic contaminations.
510 citations
TL;DR: In this paper, the authors studied how the key operational parameters: contact time, dye concentration, bentonite dosage, pH and temperature could affect the adsorption performance for the removal of Congo red (CR).
425 citations
TL;DR: In this article, the effect of pH and temperature on the drugs uptake by the adsorbent was also investigated and the results indicated that the adsorption process followed the pseudo-second-order kinetic model for the four tested drugs.
409 citations
TL;DR: A new analytical isotherm model, identified as the modified Langmuir-Freundlich (MLF) isotherms, which can be used to simulate pH-dependent adsorption effects and can help reduce modeling complexity, model development time, and computational efforts.
387 citations
TL;DR: In this article, the adsorption of reactive dyes on modified zeolite (HMDA-Z) was investigated by batch adaption experiments and the effects of pH, temperature, sorbent dosage and initial dyes concentrations were investigated.
366 citations
TL;DR: In this article, the authors used polypyrrole-polyaniline (PPy-PANI) nanofibers as adsorbent of Cr(VI) and showed that the adsorption process is spontaneous, endothermic and marked with an increase in randomness at the solid-liquid interface.
TL;DR: In this paper, a method for the removal of Rose Bengal by adsorption processes has been proposed, which is a halogen-containing fluorescein water soluble dye.
Abstract: Rose Bengal is a halogen-containing fluorescein water soluble dye, which is widely used for medical purposes. The dye, however, is highly toxic and can cause irritation, itching etc. to the human skin and eyes. It is therefore considered worthwhile to develop a systematic method for the removal of Rose Bengal by adsorption processes. The present investigation is devoted to batch as well as bulk removal of Rose Bengal. Under preliminary batch studies, adsorption isotherm measurements and kinetic studies were carried out, while for the bulk removal, a glass column was used as a fixed bed adsorber made up of Bottom Ash. Attempts were also made for the recovery of the dye from the exhausted Bottom Ash column by eluting dilute NaOH. The paper also presents a detailed procedure for activating Bottom Ash and its chemical and physical analysis. Rose Bengal showed a decrease in adsorption with increasing pH and conversely, increases in concentration, temperature, amount of adsorbent and sieve size increased the adsorption. Langmuir, Freundlich, Tempkin and D–R adsorption isotherm models were also verified, and on the basis of Langmuir constants thermodynamic parameters such as the Gibb's free energy, enthalpy and entropy of the adsorption were also calculated. A pseudo-second order process was found to operate during the adsorption. During column operations various parameters like fractional capacity of the column, mass flow rate, percentage saturation of column etc. were calculated. Desorption from the exhausted column gave almost 91% of dye recovery.
TL;DR: The virgin characteristics of OPAC were examined by pore structural analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption isotherm, elemental analysis, surface acidity/basicity and zeta potential measurement.
TL;DR: In this article, a comparison was made for the adsorption capacity of ciprofloxacin (CPX) on three types of carbon-based materials: activated carbon, carbon nanotubes and carbon xerogel.
TL;DR: In this article, an adsorbent (H-KFC) was prepared from kenaf fiber char by acid treatment using HCl (3.M), which caused an increase in the BET surface area and as a result there was an increase of the adsorption of Methylene blue dye (MB) in batch system studies.
TL;DR: In this paper, a mixture of metakaolin and alkali solution at a fixed ratio at room temperature and then pre-crashed to a fixed-radius size was used to make a geopolymer for heavy metal adsorption.
TL;DR: In this article, a graphite oxide was modified with Fe 3 O 4 and MnO 2 nanoparticles by a two-step co-precipitation reaction for removing As (III) and As (V) in water.
TL;DR: Thiol-functionalised silica-coated magnetite nanoparticles were found to be almost spherical with a uniform mesoporous structure with a pore size of ∼2.1nm and strongly responsive to an external magnetic field making separation from solution possible in less than 1min.
TL;DR: The results indicate that Langmuir model provide best correlation of experimental data, and the pseudo-second order kinetic equation could best describe the biosorption kinetics of considered heavy metals.
TL;DR: The adsorption efficiency of kaolinite for Rhodamine B (RhB) removal from aqueous solution is reported in this paper, where the optimized conditions for the removal of RhB were evaluated as: initial concentration of rhB (90mg/L), agitation time (80min), adsorbent dose (3 ǫ), pH (7), and temperature (303 k), with high correlation coefficients (R 2 ) confirmed the validity of the Langmuir isotherm, with monolayer adorption capacity ( q m ) equal to 4
TL;DR: It is found that once adsorbed, longer DNAs are much more effective in protecting AuNPs from aggregation, and DNA adsorption is also facilitated by using low pH buffers and high alcohol concentrations.
Abstract: Single-stranded DNA can be adsorbed by citrate capped gold nanoparticles (AuNPs), resulting in increased AuNP stability, which forms the basis of a number of biochemical and analytical applications, but the fundamental interaction of this adsorption reaction remains unclear. In this study, we measured DNA adsorption kinetics, capacity, and isotherms, demonstrating that the adsorption process is governed by electrostatic forces. The charge repulsion among DNA strands and between DNA and AuNPs can be reduced by adding salt, reducing pH or by using noncharged peptide nucleic acid (PNA). Langmuir adsorption isotherms are obtained, indicating the presence of both adsorption and desorption of DNA from AuNPs. While increasing salt concentration facilitates DNA adsorption, the desorption rate is also enhanced in higher salt due to DNA compaction. DNA adsorption capacity is determined by DNA oligomer length, DNA concentration, and salt. Previous studies indicated faster adsorption of short DNA oligomers by AuNPs, ...
TL;DR: In this article, a microwave assisted chemical activation of activated carbon has been attempted from coconut husk (CHAC) via microwave-assisted chemical activation, and the operational parameters including the effects of activation agents, chemical impregnation ratio (0.25-2.00), microwave power (90-800 W), and irradiation time (4-8 min) on the carbon yield and adsorption capability were investigated.
TL;DR: In this paper, a comparative study of the adsorption capacity of the chemically modified orange peel was performed against environmentally problematic metal ions, namely, Cd2+, Cu2+ and Pb2+, from aqueous solutions.
TL;DR: In this article, the MB uptake by both raw and modified Ball Clay (MBC) was investigated through batch adsorption experiment, and the results showed that MBC can be used adequately to adsorb MB more efficiently than RBC.
TL;DR: The results suggest that IJS (Z. maruritiana) is a potential low-cost adsorbent for the CR dye removal from synthetic dye wastewater.
TL;DR: In this paper, copper (II) oxide nanoparticles were prepared by thermal refluxing technique and used as an adsorbent for arsenic removal from water using TEM, BET, XRD and FTIR.
Abstract: Arsenic poisoning is a major problem in today's life. To reduce its concentration in drinking water, different metal based compounds were explored as arsenic adsorbents. In the present study, copper (II) oxide nanoparticles were prepared by thermal refluxing technique and used as an adsorbent for arsenic removal from water. Characterization of the adsorbent using TEM, BET, XRD and FTIR implied that the prepared adsorbent was in nano size and had excellent adsorption behavior with surface area of 52.11 m 2 /g. Systematic adsorption experiments were carried out with different process parameters such as contact time, adsorbent mass, pH, temperature and stirring speed and found that copper (II) oxide had very good efficiency towards arsenic adsorption. Thermodynamic parameters and adsorption kinetics were studied in detailed to know the nature and mechanism of adsorption. Results showed that the adsorption process followed pseudo second order kinetic and endothermic behavior. Adsorption equilibrium was studied with Langmuir and Freundlich isotherm models. The adsorption process followed Langmuir isotherm with an adsorption capacity of 1086.2 μg/g. A regeneration study was proposed in order to reuse the adsorbent for better economy of the process. Finally, a process design calculation is reported to know the amount of adsorbent required for efficient removal of arsenic from aqueous medium.
TL;DR: In this article, the authors used industrial wastes of coffee (untreated coffee residues, UCR) as low-cost adsorbents for the removal of dyes (reactive and basic) from single component aqueous solutions.
TL;DR: In this paper, four adsorbents (Hypercrosslinked resin MN-202, aminated polystyrene resins MN-150, macroporous resin XAD-4, and carboxylated multiwall carbon nanotube C-MWCNT) were used to remove norfloxacin from aqueous solutions.
TL;DR: It is suggested that magnetic Fe(3)O(4)@SiO(2) composite particles can be used as a potential adsorbent for sorption uranium and also provided a simple, fast separation method for removal of heavy metal ion from aqueous solution.
TL;DR: For the first time, nanoscale zero-valent iron (nZVI)-Fe(3)O(4) nanocomposites, prepared by an in situ reduction method, are employed for chromium(VI) removal in aqueous environment and the reaction mechanism was discussed in terms of the mutual benefit brought by the electron transfer from Fe(0) to Fe(3).