scholarly journals Removal of toxic metals from aqueous solution by biochars derived from long-root Eichhornia crassipes

2018 ◽  
Vol 5 (10) ◽  
pp. 180966 ◽  
Author(s):  
Qiang Li ◽  
Lizhou Tang ◽  
Jiang Hu ◽  
Ming Jiang ◽  
Xiaodong Shi ◽  
...  
Keyword(s):  
Toxic Metals ◽  
Eichhornia Crassipes ◽  
Adsorption Process ◽  
Correlation Coefficients ◽  
Sorption Ability ◽  
Different Temperatures ◽  
Lead Zinc ◽  
Pseudo Second Order ◽  
Cyano Groups ◽  
Maximum Removal

Biochars were produced from long-root Eichhornia crassipes at four temperatures: 200, 300, 400 and 500°C, referred to as LEC200, LEC300, LEC400 and LEC500, respectively. The sorption ability of lead, zinc, copper and cadmium from aqueous solutions by four kinds of biochars was investigated. All the biochars had lower values of CEC and higher values of pH. LEC500 was the best one to bind toxic metals which can be reflected in the results of SEM, BET and elemental analyser. It was also found that alkyl, carboxyl, phosphate and cyano groups in the biochars can play a role in binding metals. In addition, the sorption processes of four metals by the biochars in different metal concentration were all excellently represented by the pseudo-second-order model with all correlation coefficients R 2 > 0.95. And the sorption processes of four metals in different temperatures could be described satisfactorily by the Langmuir isotherms. According to calculated results by the Langmuir equation, the maximum removal capacities of Pb(II), Zn(II), Cu(II) and Cd(II) at 298 K were 39.09 mg g −1 , 45.40 mg g −1 , 48.20 mg g −1 and 44.04 mg g −1 , respectively. The positive value of the Δ H 0 confirmed the adsorption process was endothermic and the negative value of Δ G 0 confirmed the adsorption process was spontaneous. The sorption capacities were compared with several other lignocellulosic materials which implied the potential of long-root Eichhornia crassipes waste as an economic and excellent biosorbent for eliminating metal ions from contaminated waters.

Surface interaction of sweet potato peels (Ipomoea batata) with Cd(II) and Pb(II) ions in aqueous medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Aqueous Medium ◽  
Sweet Potato ◽  
Adsorption Process ◽  
Low Cost ◽  
Correlation Coefficients ◽  
Order Kinetic ◽  
Thermodynamic Evaluation ◽  
Dissociative Mechanism ◽  
Pseudo Second Order ◽  
Potato Peels

The removal of Cd(II) and Pb(II) ions from aqueous medium was studied using potato peels biomass. The adsorption process was evaluated using Atomic Absorption Spectrophotometer (AAS). The Vibrational band of the potato peels was studied using Fourier Transform Infrared Spectroscopy (FTIR). The adsorption process was carried out with respect to concentration, time, pH, particle size and the thermodynamic evaluation of the process was carried at temperatures of 30, 40, 50 and 60(0C), respectively. The FTIR studies revealed that the potato peels was composed of –OH, -NH, –C=N, –C=C and –C-O-C functional groups. The optimum removal was obtained at pH 8 and contact time of 20 min. The adsorption process followed Freundlich adsorption and pseudo second-order kinetic models with correlation coefficients (R2) greater than 0.900. The equilibrium adsorption capacity showed that Pb(II) ion was more adsorbed on the surface of the potato peels biomass versus Cd (II) ion (200.91 mg/g > 125.00 mg/g). The thermodynamic studies indicated endothermic, dissociative mechanism and spontaneous adsorption process. This study shows that sweet potato peels is useful as a low-cost adsorbent for the removal of Cd(II) and Pb(II) ions from aqueous medium.

scholarly journals Eggshell Powder as an Adsorbent for Removal of Fluoride from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies

2012 ◽  
Vol 9 (3) ◽  
pp. 1457-1480 ◽  
Author(s):  
R. Bhaumik ◽  
N. K. Mondal ◽  
B. Das ◽  
P. Roy ◽  
K. C. Pal ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Low Cost ◽  
Fluoride Removal ◽  
Contaminated Water ◽  
Fluoride Adsorption ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Kinetic And Thermodynamic Studies ◽  
Maximum Removal

A new medium, eggshell powder has been developed for fluoride removal from aqueous solution. Fluoride adsorption was studied in a batch system where adsorption was found to be pH dependent with maximum removal efficiency at 6.0. The experimental data was more satisfactorily fitted with Langmuir isotherm model. The kinetics and the factor controlling adsorption process fully accepted by pseudo-second-order model were also discussed. Eawas found to be 45.98 kJmol-1by using Arrhenius equation, indicating chemisorption nature of fluoride onto eggshell powder. Thermodynamic study showed spontaneous nature and feasibility of the adsorption process with negative enthalpy (∆H0) value also supported the exothermic nature. Batch experiments were performed to study the applicability of the adsorbent by using fluoride contaminated water collected from affected areas. These results indicate that eggshell powder can be used as an effective, low-cost adsorbent to remove fluoride from aqueous solution as well as groundwater.

scholarly journals Removal of Cd(II) Ions from Simulated Wastewater by HCl Modified Cucumis sativus Peel: Equilibrium and Kinetic Study

2014 ◽  
Vol 7 ◽  
pp. ASWR.S16488 ◽  
Author(s):  
Ruchi Pandey ◽  
Nasreen Ghazi Ansari ◽  
Ram Lakhan Prasad ◽  
Ramesh Chandra Murthy
Keyword(s):  
Cucumis Sativus ◽  
Adsorption Process ◽  
Order Reaction ◽  
Ion Concentration ◽  
Second Order Reaction ◽  
Monolayer Adsorption ◽  
Optimum Ph ◽  
Pseudo Second Order ◽  
Simulated Wastewater ◽  
Maximum Removal

This paper describes the adsorption of Cd(II) ions from aqueous solutions by modified Cucumis sativus peel (CSP) by HCl treatment. The optimum pH, adsorbent mass, contact time, and initial ion concentration were determined. The maximum removal efficiency was 84.85% for 20 mg/L Cd(II) ion at pH 5. The adsorption isotherms were obtained using concentrations of the metal ions ranging from 5 to 150 mg/L. The adsorption process follows Langmuir isotherm and pseudo-second-order reaction kinetics. CSPs exhibit monolayer adsorption capacity of 58.14 mg/g at 298 K. The paper also discusses the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy). Our results establish that the adsorption process was spontaneous and endothermic under normal conditions.

scholarly journals Residue Char Derived from Microwave-Assisted Pyrolysis of Sludge as Adsorbent for the Removal of Methylene Blue from Aqueous Solutions

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 979
Author(s):  
Gong Cheng ◽  
Yazhuo Li ◽  
Liming Sun ◽  
Siyi Luo ◽  
George Z. Kyzas ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Activated Sludge ◽  
Adsorption Process ◽  
Chemical Interaction ◽  
Adsorption Behavior ◽  
Microwave Assisted ◽  
Adsorption Temperature ◽  
Layer Adsorption ◽  
Different Temperatures ◽  
Pseudo Second Order

Residue char is the main by-product of the microwave-assisted pyrolysis of activated sludge and it has a high content of fixed carbon and porous structure, but little is known about its character as an absorbent. In this study, residue char of activated sludge with microwave-assisted pyrolysis was used as an adsorbent to absorb methylene blue. The effects of pyrolysis temperature, pyrolysis holding time, contact time, and adsorption temperature on the adsorption ability of residue char were investigated. Kinetics, isotherm, and thermodynamic models were also included to study the adsorption behavior. The results showed that the optimal pyrolysis condition was 15 min and 603 °C, and the adsorption capacity reached up to 80.01 mg/g. The kinetics analyses indicated the adsorption behavior followed the pseudo-second-order kinetics model and the adsorption process was mainly due to chemical interaction. The adsorption isotherm was described by Freundlich model and thus, its process was multimolecular layer adsorption. Furthermore, the thermodynamics parameters (ΔG0, ΔH0, and ΔS0) at different temperatures indicated that the nature of the adsorption process was endothermic and spontaneous.

Removal of 4-nitrophenol from aqueous solution by adsorption onto activated carbon prepared from Acacia glauca sawdust

2015 ◽  
Vol 73 (4) ◽  
pp. 955-966 ◽  
Author(s):  
Prashant T. Dhorabe ◽  
Dilip H. Lataye ◽  
Ramakant S. Ingole
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Adsorption Process ◽  
Enthalpy Change ◽  
Optimum Dose ◽  
Batch Adsorption ◽  
Gibbs Free Energy Change ◽  
Pseudo Second Order ◽  
Percentage Removal ◽  
Maximum Removal

The present paper deals with a complete batch adsorption study of 4-nitrophenol (4NP) from aqueous solution onto activated carbon prepared from Acacia glauca sawdust (AGAC). The surface area of the adsorbent determined by methylene blue method is found to be 311.20 m2/g. The optimum dose of adsorbent was found to be 2 g/l with 4NP uptake of 25.93 mg/g. The equilibrium time was found to be 30 minutes with the percentage removal of 96.40 at the initial concentration of 50 ppm. The maximum removal of 98.94% was found to be at pH of 6. The equilibrium and kinetic study revealed that the Radke–Prausnitz isotherm and pseudo second order kinetics model fitted the respective data well. In the thermodynamic study, the negative value of Gibbs free energy change (−26.38 kJ/mol at 30°C) and enthalpy change (−6.12 kJ/mol) showed the spontaneous and exothermic nature of the adsorption process.

scholarly journals ADSORPTION OF PARAQUAT DICHLORIDE TO KAOLIN PARTICLES AND TO MIXTURES OF KAOLIN AND HEMATITE PARTICLES IN AQUEOUS SUSPENSIONS

2015 ◽  
Vol 1 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Dina Alexandra Martins ◽  
Manuel Simões ◽  
Luís Melo
Keyword(s):  
Adsorption Process ◽  
Correlation Coefficients ◽  
Water Security ◽  
Inhibitory Effect ◽  
Order Model ◽  
Short Period ◽  
Initial Ph ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Special Expertise

Deliberate contamination with pesticides is a potential risk to water security, due to the availability of these contaminants and the fact that they do not need special expertise to handle or apply. Adsorption of the herbicide paraquat from an aqueous solution to suspended particles of kaolin and kaolin/hematite mixture was investigated by kinetic and equilibrium assays, taking into consideration several parameters such as initial pH, sorbent dosage and agitation speed. The results showed that the adsorption process is quite fast, reaching an 18% reduction in paraquat concentration in a very short period of time. The addition of hematite particles to kaolin suspension had no apparent effect on the maximum amount of paraquat adsorbed. Kinetic parameters were determined by fitting the pseudo-second order model to the experimental data (correlation coefficients close to 1). Isotherm studies indicate an inhibitory effect, promoted by hematite particles, that was not detected in the adsorption assays. Equilibrium data was best adjusted using the Langmuir model which yielded higher correlation coefficient values and smaller normalized standard deviations.

Studies on Adsorption of Tyrosine on Multi-Wall Carbon Nanotubes

2011 ◽  
Vol 179-180 ◽  
pp. 1396-1401
Author(s):  
Zhi Biao Feng ◽  
Ren Jiao Han ◽  
Jing Long Wang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Multi Wall Carbon Nanotubes ◽  
Different Temperatures ◽  
Pseudo Second Order ◽  
Rate Controlling Step ◽  
Mechanism Of Sorption

The thermodynamics and kinetics properties and mechanism of sorption process were studied for adsorpting tyrosine in aqueous solution with multi-wall carbon nanotubes (MWCNTs), and the adsorption isotherms at different temperatures were determined. The results showed that the adsorption of the tyrosine in aqueous solution obeys well with the Freundlich isotherm, The thermodynamic parameters indicated that the adsorption reaction was a spontaneous, exothermal and decreasing entropy process,and the adsorption process had an obvious physisorption characteristic.The pseudo-second-order equation provided the best correlation for the adsorption process, being in agreement with adsorption as the rate controlling step.

scholarly journals Comparative study on As(III) and As(V) adsorption by CO32--intercalated Fe/Mn-LDHs from aqueous solution

2021 ◽  
Author(s):  
Yan Tian ◽  
Guifeng Liu ◽  
Yingying Gao ◽  
Yaru Wang ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Correlation Coefficients ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Metal Mining ◽  
Mining Areas ◽  
The People ◽  
Order Kinetic Model ◽  
Lead Zinc ◽  
Pseudo Second Order ◽  
Double Hydroxide

Abstract Arsenic pollution prevails in rivers and reservoirs in nonferrous metal mining areas, especially in lead–zinc mining areas, which affects the health of the people residing in such areas. Arsenic usually exists as As(III) and As(V) in water, and the adsorption of As(III) and As(V) changes with the type of adsorbent used. In this work, we report a novel adsorbent Fe/Mn–CO3-layered double hydroxide (Fe/Mn–CO3-LDH) composite that can efficiently remove both As(III) and As(V) from water. When the initial concentrations of As(III) and As(V) were 5, 10 and 50 mg/L, the adsorption capacities were 10.12–53.90 and 10.82–48.24 mg/g in the temperature range of 25–45 °C, respectively. The adsorption kinetics conformed well to the pseudo-second-order kinetic model, with all of the fitted correlation coefficients being above 0.998 for all the three initial concentrations (5, 10 and 50 mg/L) tested, suggesting a chemisorption-dominated process. The adsorption isotherms of As(III) and As(V) by Fe/Mn–CO3-LDHs conformed better to the Freundlich model than to the Langmuir one, indicating a heterogeneous reversible adsorption process. The theoretical maximum adsorption capacity increased with the increase in temperature. During adsorption, As(III) was partially converted to As(V), which was further interacted with intralayer anions. While the electrostatic attraction played an important role in the adsorption of As(V).

scholarly journals A comparative biosorption study of sulfide (S-2) by using Lagenaria siceraria fruit based raw biosorbent

2017 ◽  
Vol 52 (4) ◽  
pp. 309-320
Author(s):  
P Dar ◽  
A Dar ◽  
D Ahmed ◽  
AM Dar
Keyword(s):  
Adsorption Process ◽  
Raw Materials ◽  
Order Kinetic ◽  
Lagenaria Siceraria ◽  
Batch Mode ◽  
Adsorbent Dosage ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Sulfide Ions ◽  
Maximum Removal

In batch mode, the adsorption characteristics of S2- ions on Lagenaria siceraria mesocarp, pedicle and peel as raw materials have been studied in comparison to remove sulfide ions from tanneries waste water, under various parameters such as adsorbent dosage, contact time, agitation speed and pH. Maximum removal efficiency (70.96%) was observed on L. Siceraria peel followed by pedicle (51.58%) and mesocarp (29.57%) for adsorbent dosage of 0.10 g/L peel for 50 ml solution of sulfide (20 mg/L). The adsorption process was rapid, and it reached equilibrium in early 20-35 min for all adsorbents. Freundlich and Langmuir adsorption isotherms were employed for mathematical description of the adsorption equilibrium and to explain mechanism of adsorption. The maximum amounts of sulfide ions adsorbed, as evaluated by Langmuir isotherm, was 1.0436 mg/g of LS pedicle, 0.886 mg/g of peel and 0.843 mg/g of pedicle. The adsorption process conforms well to a pseudo second order kinetic model with best adsorption results at pH 8.Bangladesh J. Sci. Ind. Res. 52(4), 309-320, 2017

Removal of PCP-Na from aqueous systems using monodispersed pompon-like magnetic nanoparticles as adsorbents

2013 ◽  
Vol 68 (12) ◽  
pp. 2704-2711
Author(s):  
Yu Liu ◽  
Hongbing Yu ◽  
Sihui Zhan ◽  
Shengjun Li ◽  
Hui Yang ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Magnetic Nanoparticles ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Solvothermal Method ◽  
Aqueous Media ◽  
Sodium Pentachlorophenate ◽  
Pseudo Second Order ◽  
Ph Dependent ◽  
Maximum Removal

Novel monodispersed pompon-like magnetite/chitosan (Fe3O4/CS) composite nanoparticles were synthesized by a solvothermal method and used as adsorbents for the removal of toxic sodium pentachlorophenate (PCP-Na) from aqueous media. The adsorption behavior of PCP-Na on Fe3O4/CS obeyed the Langmuir isotherm and fitted the pseudo-second-order kinetics model. Thermodynamic parameters showed that the adsorption process was exothermic and spontaneous. Moreover, the adsorption was strongly pH-dependent. The results of XPS, thermodynamics, pH-dependent and desorption studies suggested that electrostatic attraction, hydrogen bonding and π-π interactions were all believed to play a role in PCP-Na adsorption on Fe3O4/CS. Having a saturation magnetization of 22.2 emu · g−1, the Fe3O4/CS can be easily separated from water with magnets within 2 min. The adsorption equilibrium was achieved quite rapidly (within 30 min) and the maximum removal of PCP-Na (91.5%) was obtained at 25 °C and pH 6.5. The Fe3O4/CS investigated can be used to remove PCP-Na and other contaminants from wastewater.

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