Magnetic nanocomposite beads: synthesis and uptake of Cu(II) ions from aqueous solutions

2015 ◽  
Vol 93 (3) ◽  
pp. 289-296 ◽  
Author(s):  
Al-Sayed A. Bakr ◽  
Yasser M. Moustafa ◽  
Mostafa M.H. Khalil ◽  
Mohamed M. Yehia ◽  
Eman A. Motawea

Sodium alginate and magnetic iron oxide nanoparticles were combined to produce magnetic nanocomposite beads that were used for the removal of Cu(II) from aqueous solutions at a temperature of 25 °C and a stirring rate of 150 rpm. The different parameters affecting the adsorption capacity of the synthesized material such as contact time (30–270 min), pH (3–7), adsorbent dosage (5–10 g per 50 mL of wet beads), and initial Cu(II) concentration (50–450 mg/L) were investigated. Of all of the variables, the solution pH has the most significant effect on the adsorption capacity, particularly in the range of 4–6. Response surface methodology was used for modeling and optimizing the uptake process. While the experimental data were well described by the pseudo-second-order model, the adsorption isotherms were better fitted by the Langmuir equation. The results revealed that the maximum removal percentage was 92.6% from the initial Cu(II) concentration (150 mg/L) at pH 6, adsorbent dose (8.0 g/50 mL), and contact time (210 min). Therefore, the synthesized magnetic nanocomposite product could act as a highly effective nanoadsorbent in Cu(II) removal from the aqueous solutions.

2012 ◽  
Vol 66 (8) ◽  
pp. 1699-1707 ◽  
Author(s):  
A. K. Giri ◽  
R. K. Patel ◽  
P. C. Mishra

In this work, the biosorption of As(V) from aqueous solutions by living cells of Bacillus cereus has been reported. The batch biosorption experiments were conducted with respect to biosorbent dosage 0.5 to 15 g/L, pH 2 to 9, contact time 5 to 90 min, initial concentration 1 to 10 mg/L and temperature 10 to 40 °C. The maximum biosorption capacity of B. cereus for As(V) was found to be 30.04 at pH 7.0, at optimum conditions of contact time of 30 min, biomass dosage of 6 g/L, and temperature of 30 ± 2 °C. Biosorption data were fitted to linearly transformed Langmuir isotherms with R2 (correlation coefficient) >0.99. Bacillus cereus cell surface was characterized using AFM and FTIR. The metal ions were desorbed from B. cereus using both 1 M HCl and 1 M HNO3. The pseudo-second-order model was successfully applied to predict the rate constant of biosorption.


2017 ◽  
Vol 13 ◽  
pp. 323-329 ◽  
Author(s):  
Anastasiya E. Kucherova ◽  
Irina V. Romantsova ◽  
Alexandr E. Burakov ◽  
Nariman R. Memetov ◽  
Mikhail N. Krasnyansky

The present paper describes an investigation of the adsorption of lead ions (Pb2+) on graphene-based nanocomposites obtained via exfoliation of hydrolyzed expanded graphite intercalation compound. Three types of these nanocomposites - suspension of graphene nanoplatelets (SGN), paste of multi-layered oxidized graphene (PMOG), and paste of few-layered oxidized graphene (PFOG) - were used to extract Pb2+ from 1,040 mg L-1 aqueous solutions of Pb (NO3)2, and the kinetic of the Pb2+ adsorption was studied. It was found that the kinetic data are best fitted by the pseudo-second-order model. The adsorption equilibrium was achieved within 30 min under normal conditions. The maximum Pb2+ adsorption capacity of SGN, PMOG and PFOG was found to be 457, 103 and 38 mg g-1, respectively. Considering the obtained results, it can be assumed that the phenolic and hydroxyl oxygen-containing functional groups located at the surface of the adsorption materials under study play an important role in the Pb2+ removal process.


2020 ◽  
Vol 10 (10) ◽  
pp. 3437
Author(s):  
Jude Ofei Quansah ◽  
Thandar Hlaing ◽  
Fritz Ndumbe Lyonga ◽  
Phyo Phyo Kyi ◽  
Seung-Hee Hong ◽  
...  

We assessed the applicability of rice husk (RH) to remove cationic dyes, i.e., methylene blue (MB) and crystal violet (CV), from water. RH thermally treated at 75 °C showed a higher adsorption capacity than that at high temperatures (300–700 °C). For a suitable CV-adsorption model, a pseudo-first-order model for MB adsorption was followed by the kinetics adsorption process; however, a pseudo-second-order model was then suggested. In the qt versus t1/2 plot, the MB line passed through the origin, but that of CV did not. The Langmuir isotherm model was better than the Freundlich model for both dye adsorptions; furthermore, the adsorption capacity for MB and CV was 24.48 mg/g and 25.46 mg/g, respectively. Thermodynamically, the adsorption of both MB and CV onto the RH was found to be spontaneous and endothermic. This adsorption increased insignificantly on increasing the solution pH from 4 to 10. With an increasing dosage of the RH, there was an increase in the removal percentages of MB and CV; however, adsorption capacity per unit mass of the RH was observed to decrease. Therefore, we conclude that utilizing RH as an available and affordable adsorbent is feasible to remove MB and CV from wastewater.


2012 ◽  
Vol 9 (3) ◽  
pp. 1266-1275 ◽  
Author(s):  
J.Raffiea Baseri ◽  
P.N. Palanisamy ◽  
P. Sivakumar

In this research, Polyaniline coated sawdust (Polyaniline nano composite) was synthesized via direct chemical polymerization and used as an adsorbent for the removal of acid dye (Acid Violet 49) from aqueous solutions. The effect of some important parameters such as pH, initial concentration of dye, contact time and temperature on the removal efficiency was investigated in batch adsorption system. The adsorption capacity of PAC was high (96.84 %) at a pH of 3-4. The experimental data fitted well for pseudo second order model. Langmuir model is more appropriate to explain the nature of adsorption with high correlation coefficient. The Energy of activation from arrehenius plot suggested that the adsorption of AV49 onto PAC involves physisorption mechanism.


2011 ◽  
Vol 347-353 ◽  
pp. 281-284
Author(s):  
Peng Ge ◽  
Li Juan Wan ◽  
Ya Jing Xu

Among the investigated clays and minerals (kaolinite, natural zeolite, manual zeolite, bentonite, sepiolite, sepiolite amianthus, tremolite amianthus, vermiculite and baritite), the baritite clay was selected as the optimal adsorbent for aqueous Cr (VI). The Cr (VI) adsorption capacity on baritite clay reached as high as 39.01 mg∙g−1 at 20°C. Then the adsorption kinetics of Cr (VI) by the baritite clay were investigated in details. Results showed that the pseudo-second-order model was a suitable description for the adsorption kinetics and fitted well with the experimental data.


2018 ◽  
Vol 43 (6) ◽  
pp. 623-631 ◽  
Author(s):  
Reza Mahini ◽  
Hossein Esmaeili ◽  
Rauf Foroutan

Abstract Objective The presence of dyes in the water is toxic and harmful to human body so, it must be removed from the water. In the present study, the removal of methyl violet (MV) from aqueous solutions using brown algae “Padina sanctae-crucis” was investigated. Materials and methods The rate of adsorption was investigated under various parameters such as contact time (5–200), pH (2–11), dye concentration (10–60 mg/L), amount of adsorbent (0.25–5 g/L) and temperature (25–45°C). Results The maximum adsorption was achieved in 10 mg/L, pH=8 and adsorbent dose 2 g/L and 80 min contact time for removal of MV from aqueous solutions. Kinetic studies showed that the pseudo second-order model describes adsorbent kinetic behavior better. Besides, experimental data have been modeled using Langmuir and Freundlich isotherms and the results showed that both models are proper to describe adsorption isotherm behavior. In addition, the equilibrium study shows that the adsorption was physical and favorable. Moreover, a thermodynamic study revealed that the adsorption process is exothermic and spontaneously in nature. Furthermore, Maximum adsorption capacity using adsorbent was 10.02 mg/g. Conclusions It could be concluded that the P. sanctae-crucis biomass is a good adsorbent for removing MV dyes from aqueous solutions.


2016 ◽  
Vol 73 (9) ◽  
pp. 2132-2142 ◽  
Author(s):  
F. Ferrarini ◽  
L. R. Bonetto ◽  
Janaina S. Crespo ◽  
M. Giovanela

Adsorption has been considered as one of the most effective methods to remove dyes from aqueous solutions due to its ease of operation, high efficiency and wide adaptability. In view of all these aspects, this study aimed to evaluate the adsorption capacity of a halloysite-magnetite-based composite in the removal of Congo red dye from aqueous solutions. The effects of stirring rate, pH, initial dye concentration and contact time were investigated. The results revealed that the adsorption kinetics followed the pseudo-second-order model, and equilibrium was well represented by the Brunauer–Emmett–Teller isotherm. The thermodynamic data showed that dye adsorption onto the composite was spontaneous and endothermic and occurred by physisorption. Finally, the composite could also be regenerated at least four times by calcination and was shown to be a promising adsorbent for the removal of this dye.


2010 ◽  
Vol 178 ◽  
pp. 8-16
Author(s):  
Liang Dong Feng ◽  
Bo Qing Chen ◽  
Ying Ying Shi ◽  
Ying Wei Guo ◽  
Jing Huang ◽  
...  

1, 10-phenanthroline and triethylamine modified palygorskites were prepared by microwave irradiation, and characterized with FT-IR technique. The effects of contact time, adsorbent dosage, and pH value of the initial solution on the adsorption characters of Mn2+ were investigated. The adsorption of Mn2+ from aqueous solutions using 1, 10-phenanthroline or triethylamine modified palygorskites were investigated. Experiment results indicated that 1,10-phenanthroline and triethylamine molecules have been successfully grafted to palygorskite. The adsorption was rapid during the first 5 minuts and equilibrium were attained within 60 minutes in the initial concentration of Mn2+ of 50 and 100 mg•L-1, and fast adsorption in the first 10 minutes and slowly increased with the contact time due to the adsorption of palygorskite. The 1, 10-phenanthroline modified palygorskites had higher adsorption capacity than triethylamine modified palygorskites. Compared with natural palggorskites, the Mn2+ ions adsorption capacities of palggorskite modified by 1, 10-phenanthroline or triethylamine were significantly improved. There were less difference in the adsorption capacity between different dasages of 1, 10-phenanthroline modified palygorskites, but the adsorption capacity of Mn2+ adsorbed onto triethylamine modified palygorskites decreased with increasing the dosages. A Lagergren pseudo-second order model best described the kinetics of adsorption of Mn2+ onto the modified palygorskites.


2021 ◽  
Vol 60 (1) ◽  
pp. 365-376
Author(s):  
Xiaoxing Zhang ◽  
Hui Liu ◽  
Jin Yang ◽  
Li Zhang ◽  
Binxia Cao ◽  
...  

Abstract Iron phosphate-modified pollen microspheres (pollen@FePO4) were prepared and applied as sorbents for the removal of heavy metals (Cd2+ and Pb2+) from the aqueous solution. Batch sorption studies were conducted to investigate the effects of solution pH, contact time, sorbent dosage, and metal concentration on the adsorption process. The sorption of Cd2+ and Pb2+ ions on pollen@FePO4 corresponds to the pseudo-second-order model and Langmuir isotherm, which is similar to the unmodified pollen. At pH 5.92, pollen@FePO4 offers maximum adsorption capacities of 4.623 and 61.35 mg·g−1 for Cd2+ and Pb2+, respectively. The faster sorption kinetics and higher adsorption capacities of Cd2+ and Pb2+ ions onto pollen@FePO4 than pollen indicates that it might be a promising material for the removal of heavy metal ions in aqueous solutions. The possible adsorption mechanism involves electrostatic and chemisorption for Cd2+ and mainly complexion for Pb2+.


2012 ◽  
Vol 610-613 ◽  
pp. 551-555 ◽  
Author(s):  
Qi Jun Zhou ◽  
Ran Xu

Meta-aramid/poly (acylic acid) (PMIA/PAA) composite nanofibrous membranes with diameter between 50-100 nm have been fabricated by electrospinning method. The effect of contact time, temperature, pH and concentration of 2,4-dichlorophenol on the adsorption capacity of the membranes were investigated. The equilibrium adsorption capacity of 2,4-dichlorophenol on PMIA/PAA nanofibrous membranes is 251.61 mg/g. Acidic pH was favorable for the 2,4-dichlorophenol adsorption. Its desorption rate reached 74% in 45 min. After five regeneration cycles, the removal rate of 2,4-dichlorophenol still maintained above 65%. The adsorption of 2,4-dichlorophenol on the membranes fit the Freundlich isotherm model best. Its adsorption kinetics followed a pseudo-second-order model.


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