scholarly journals Preparation of CoFe2O4@Carboxymethylcellulose/HZSM-5 as a Novel Nano Magnetic Adsorbent for Metronidazole Removal: Isotherm, Kinetic and Thermodynamic Study

Author(s):  
Alireza Nasiri ◽  
Mohammad Reza Heidari ◽  
Neda Javid ◽  
Ghazal Yazdanpanah

Abstract In this research CoFe2O4@CMC/ HZSM-5 synthesized in the presence of Carboxymethylcellulose as a biopolymer in the green conditions as a new nanomagnetic adsorbent for metronidazole removal from aqueous media. Physical and chemical structure of adsorbent was investigated by FTIR, FESEM, EDS, Mapping, TEM, XRD, VSM, BET and TGA techniques. The results indicated that 94% of the metronidazole concentration removed by CoFe2O4@CMC/HZSM-5 in the optimal conditions including pH 6, temperature 20oC, metronidazole concentration 50 mg/L, contact time 60 min and adsorbent dose 2 g/L. The resulting data from adsorption experimental experiments had better correlated with the Freundlich isotherm and pseudo-second order kinetic. Also, the thermodynamic study demonstrated that the adsorption process was an endothermic process and had a physical mechanism. As well as, the achieved findings demonstrated that following six adsorption runs, the adsorbent chemical structure had no change and the nanomagnetic adsorbent efficiency in the removal process had a slight decrease. CoFe2O4@CMC/HZSM-5 magnetic nanocomposite had effective adsorption capacity for metronidazole removal.

Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.


Author(s):  
Jurgita Seniūnaitė ◽  
Rasa Vaiškūnaitė ◽  
Kristina Bazienė

Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.


Author(s):  
Fei Huang ◽  
Lu Zhang ◽  
Ren-Ren Wu ◽  
Si-Ming Zhang ◽  
Rong-Bo Xiao

The present study investigated the adsorption of Cd2+ by nonmagnetic and magnetic biochars (CMB and M-CMB) derived from chicken manure, respectively. The adsorption characteristics were investigated as a function of initial pH, contact time, initial Cd2+ concentration and magnetic separation. Adsorption process of both biochars were better described by Pseudo-second-order kinetic equation and Freundlich isotherm model, which were spontaneous and endothermic in nature. It was found that maximum capacities were 60.69 and 41.07 mg/g obtained at the initial Cd2+ concentration of 180 mg/L for CMB and M-CMB, and the turbidity of adsorption-treated solution was reduced from 244.3 to 11.3 NTU after magnetic separation of 0.5 min. These indicated that M-CMB had lower adsorption capacity of Cd2+ than CMB, though it was successfully separated from the treated solutions. Furthermore, both biochars before and after adsorption were analyzed by SEM-EDS, XRD and FTIR. Adsorption mechanisms mainly included precipitation, ion-exchange, complexation and Cπ-coordination, in which precipitation and ion-exchange dominated the adsorption process by CMB, while in M-CMB, precipitation was always predominant mechanism, followed by ion-exchange. The two other mechanisms of complexation and Cπ-coordination were trivial in both biochars, jointly contributing 7.21% for CMB and 5.05% for M-CMB to total adsorption. The findings deepen our understanding of the mechanisms governing the adsorption process, which are also important for future practical applications in the removal of heavy metals from wastewater by the biochars.


Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 454 ◽  
Author(s):  
Aili Wang ◽  
Shuhui Li ◽  
Hou Chen ◽  
Ying Liu ◽  
Xiong Peng

This paper reports the successful construction of novel polymerizable ionic liquid microemulsions and the in situ synthesis of poly(ionic liquid) adsorbents for the removal of Zn2+ from aqueous solution. Dynamic light-scattering data were used to confirm the polymerization media and to illustrate the effect of the crosslinker dosage on the droplet size of the microemulsion. FTIR and thermal analysis were employed to confirm the successful preparation of the designed polymers and characterize their thermostability and glass transition-temperature value. The optimization of the adsorption process indicates that the initial concentration of Zn2+, pH, adsorbent dosage and contact time affected the adsorption performance of poly(ionic liquid)s toward Zn2+. Furthermore, our research revealed that the adsorption process can be effectively described by the pseudo second-order kinetic model and the Freundlich isotherm model.


2010 ◽  
Vol 62 (8) ◽  
pp. 1888-1897 ◽  
Author(s):  
Nan Chen ◽  
Zhenya Zhang ◽  
Chuanping Feng ◽  
Miao Li ◽  
Rongzhi Chen ◽  
...  

Kanuma mud, a geomaterial, is used as an adsorbent for the removal of fluoride from water. The influences of contact time, solution pH, adsorbent dosage, initial fluoride concentration and co-existing ions were investigated by batch equilibration studies. The rate of adsorption was rapid with equilibrium being attained after about 2 h, and the maximum removal of fluoride was obtained at pH 5.0–8.0. The Freundlich isotherm model was found to represent the measured adsorption data well. The negative value of the thermodynamic parameter ΔG suggests the adsorption of fluoride by Kanuma mud was spontaneous, the endothermic nature of adsorption was confirmed by the positive ΔH value. The negative ΔS value for adsorbent denoted decreased randomness at the solid/liquid interface. The adsorption process using Kanuma mud followed the pseudo-second-order kinetic model. Fluoride uptake by the Kanuma mud was a complex process and intra-particle diffusion played a major role in the adsorption process. It was found that adsorbed fluoride could be easily desorbed by washing the adsorbent with a solution of pH 12. This indicates the material could be easily recycled.


2021 ◽  
Author(s):  
Mohammad Dinari ◽  
Shirin Shabani

Abstract Herein, we report the synthesis of Cu-Ca-Al/NO3-based layered double hydroxide through co-precipitation methodology. The prepared layered double hydroxide was then modified with itaconic acid. The physicochemical properties of the prepared materials were studied using Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray diffraction analysis, thermogravimetric analysis, and nitrogen adsorption/desorption technique. The prepared materials were then applied as novel adsorbents for the removal of Congo red as a model of an anionic dye from aqueous media. To reach maximum adsorption, the effect of parameters including sample solution pH, adsorbent amount, contact time, and initial concentration of Congo red on the adsorption process was investigated. Kinetic studies were also conducted to study the mechanism of adsorption. In this regard, the kinetic models of pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion were studied. The results showed that the adsorption of Congo red onto Cu-Ca-Al-LDH and LDH-ITA adsorbents followed the pseudo-second-order kinetic model. To evaluate the equilibrium adsorption data, different isotherms including Langmuir, Freundlich, and Dubinin-Radushkevich were also applied. The data revealed that the Freundlich isotherm provided the best fit with the equilibrium data of both adsorbents. Maximum adsorption capacities of 81 and 84 mg g− 1 were obtained using Cu-Ca-Al-LDH and LDH-ITA adsorbents, respectively.


Author(s):  
Nnaemeka John Okorocha ◽  
J. Josphine Okoji ◽  
Charles Osuji

The potential of almond leaves powder, (ALP) for the removal of Crystal violet (CV) and Congo red (CR) dyes from aqueous solution was investigated. The adsorbent (ALP) was characterized by FTIR and SEM analysis. Batch adsorption studies were conducted and various parameters such as contact time, adsorbent dosage, initial dye concentration, pH and temperature were studied to observe their effects in the dyes adsorption process. The optimum conditions for the adsorption of CV and CR dyes onto the adsorbent (ALP) was found to be: contact time (100mins), pH (10.0), temperature (343K) for an initial CV dye concentration of 50mg/L using adsorbent dose of 1.0g and contact time (100mins), pH (2.0), temperature (333K) for an initial CR dye concentration of 50mg/L using adsorbent dose 1.0g respectively. The experimental equilibrium adsorption data fitted best and well to the Freundlich isotherm model for both CV and CR dyes adsorption. The maximum adsorption capacity of ALP was found to be 22.96mg/g and 7.77mg/g for the adsorption of CV and CR dyes respectively. The kinetic data conformed to the pseudo-second-order kinetic model. Thermodynamic quantities such as Gibbs free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were evaluated and the negative values of ΔG0obtained for both dyes indicate the spontaneous nature of the adsorption process while the positive values of ΔH0and ΔS0obtained indicated the endothermic nature and increased randomness during the adsorption process respectively for the adsorption of CV and CR onto ALP. Based on the results obtained such as good adsorption capacity, rapid kinetics, and its low cost, ALP appears to be a promising adsorbent material for the removal of CV and CR dye stuff from aqueous media.


2020 ◽  
Vol 234 (3) ◽  
pp. 485-503
Author(s):  
Abdul Malik ◽  
Abbas Khan ◽  
Nasrullah Shah ◽  
Muhammad Sufaid Khan

AbstractThe use of indigenous natural materials and their modification toward fruitful application is one of the important subjects. Thermal modification of Rice Husk at 400 oC resulted into Rice Husk Char (RHC) which was chemically modified with KOH and was labeled as KOH Modified Rice Husk Char (KMRHC). Both RHC and KMRHC were characterized by using, Fourier transformed infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-rays (EDX) and X-ray diffraction (XRD) before and after their use as adsorbents. The prepared material was applied for the removal of toxic dyes, Direct Blue (DB) and Titan Yellow (TY) from aqueous media. The maximum adsorption capacity of DB and TY dyes on KMRHC were inspected as 30.9 mg/g and 28.6 mg/g, respectively at pH 4 using initial dye concentrations of 80 mg/L containing 2500 mg/L of the adsorbent dose with agitation speed of 240 rpm at 303 K. At the same experimental conditions the highest percentage removal of DB and TY on the adsorbent were observed as 96.6% and 89.3%, respectively. Thermodynamics studies of the adsorption of DB and TY dyes on KMRHC inferred for exothermic and spontaneous process. The value of ΔS is negative which suggested that randomness decreases at the interface of adsorbent-adsorbate during the adsorption. The kinetics study indicated that the experimental data of the adsorption process for both dyes, best fits to pseudo-second order kinetic model. The equilibrium data was tested on Langmuir, Freundlich and Temkin adsorption isotherm models. It was observed that the data are best fit to the Langmuir isotherm model (R2 > 0.99), which suggested that the adsorption process is dominated by chemisorption approach. The overall results suggest that various parameters of the adsorption process were not only affected by the variation in experimental conditions but also by the chemical structure of the adsorbate molecules for the same adsorbent.


Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 882 ◽  
Author(s):  
Haifeng Wen ◽  
Daofang Zhang ◽  
Lin Gu ◽  
Haixiang Yu ◽  
Minmin Pan ◽  
...  

Sludge-derived activated carbon (SAC) was prepared by Fenton activation and calcination, and used as adsorbent to eliminate Eriochrome Black T (EBT) dye from aqueous media. The characterization results indicated that the produced SAC had a porous structure, high specific surface area, and abundant functional groups on its surface. The adsorption process was affected by pH, adsorbent dosage, time, and temperature. The adsorption capacity increased with temperature, and the highest adsorption capacity reached 178.2 mg·g−1 in 48 h at 318 K and pH 6. The results of the adsorption isotherm, kinetic, and thermodynamic analyses revealed that the adsorption of EBT onto SAC was naturally endothermic and spontaneous, involved both physical and chemical processes, and belonged mostly to the multilayer type of adsorption.


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