scholarly journals Novel lignocellulosic wastes for comparative adsorption of Cr(VI): equilibrium kinetics and thermodynamic studies

2017 ◽  
Vol 19 (2) ◽  
pp. 6-15 ◽  
Author(s):  
Hajira Haroon ◽  
Syed Mubashar Hussain Gardazi ◽  
Tayyab Ashfaq Butt ◽  
Arshid Pervez ◽  
Qaisar Mahmood ◽  
...  
Keyword(s):  
Active Sites ◽  
Low Cost ◽  
Liquid Interface ◽  
Order Kinetic ◽  
Batch Mode ◽  
Adsorption Sites ◽  
Equilibrium Data ◽  
Controlled Adsorption ◽  
Solid Liquid Interface ◽  
Solid Liquid

Abstract Cr(VI) adsorption was studied for abundantly available low-cost lignocellulosic adsorbents in Pakistan namely, tobacco stalks (TS), white cedar stem (WCS) and eucalyptus bark (EB). Several process variables like contact time, adsorbent dose, pH, metal concentration, particle size and temperature were optimized in batch mode. EB showed high Cr(VI) adsorption of 63.66% followed by WCS 62% and TS 57% at pH 2, which is higher than most of the reported literature. Langmuir isotherm (R2 = 0.999) was well fitted into the equilibrium Cr(VI) data of EB, suggesting homogeneous active sites and monolayer coverage of Cr(VI) onto the EB surface. Freundlich (R2 = 0.9982) isotherm was better fitted to the equilibrium data of TS and WCS, revealing the adsorption sites with heterogeneous energy distribution and multilayer Cr(VI) adsorption. Moreover, the Cr(VI) adsorption of studied adsorbents followed the pseudo-second order kinetic model. Thermodynamic properties were investigated in two temperature ranges, i.e., T1 (303–313 K) and T2 (313–323 K). TS and EB showed the exothermic at T1 and endothermic reactions at T2 with entropy controlled adsorption at the solid-liquid interface, and WCS exhibited an opposite thermal trend with decreasing disorderness at solid-liquid interface as temperature rises. Gibbs free energy (ΔG>0) confirmed the non-spontaneous adsorption process for all studied adsorbents.

pH-Controlled Adsorption of Polyelectrolyte Diblock Copolymers at the Solid/Liquid Interface

Langmuir ◽  
2000 ◽  
Vol 16 (14) ◽  
pp. 5980-5986 ◽  
Author(s):  
D. A. Styrkas ◽  
V. Bütün ◽  
J. R. Lu ◽  
J. L. Keddie ◽  
S. P. Armes
Keyword(s):  
Diblock Copolymers ◽  
Liquid Interface ◽  
Controlled Adsorption ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Ph Controlled

scholarly journals Adsorption of an anionic dye (Congo red) from aqueous solutions by pine bark

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Khaoula Litefti ◽  
M. Sonia Freire ◽  
Mostafa Stitou ◽  
Julia González-Álvarez
Keyword(s):  
Congo Red ◽  
Low Cost ◽  
Pine Bark ◽  
Point Of Zero Charge ◽  
Order Kinetic ◽  
Batch Mode ◽  
Adsorbent Dosage ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Cr Concentration

Abstract Pinus pinaster bark, an abundant by-product from the timber industry, has been studied as a potential low-cost adsorbent for the removal of Congo red (CR) dye from wastewaters. Surface morphological and physico-chemical characteristics of pine bark were analysed using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), determination of the point of zero charge (pHPZC) and elemental analysis. Assays were performed to determine the wavelength for the maximum absorbance and the stability with time of CR solutions depending on concentration and/or pH, which resulted to be a very significant parameter. Adsorption studies were conducted on batch mode to study the effect of contact time (till 7 days), pH (2–9), adsorbent dosage (1–10 g L−1) and temperature (25–60 °C). The bark adsorption capacity at equilibrium varied between 0.3 and 1.6 mg g−1 and the equilibrium adsorption percentage between 23.4 and 100% depending on adsorbent dosage, temperature and pH at an initial CR concentration of 5 mg L−1. Kinetic data for the removal of CR by pine bark were best fitted by the pseudo-second-order kinetic model. The equilibrium data fitted well with the Freundlich model. Thermodynamic analysis indicated that the adsorption process is exothermic and spontaneous.

Mathematical Modeling of Adsorption of Co2+ Ions on Sugarcane Bagasse

2017 ◽  
Vol 14 (1) ◽  
pp. 6033-6040
Author(s):  
Hamid Taouil
Keyword(s):  
Mathematical Modeling ◽  
Metal Ions ◽  
Sugarcane Bagasse ◽  
Adsorption Process ◽  
Liquid Interface ◽  
Order Kinetic ◽  
Adsorption Of Co2 ◽  
Modeling Of Adsorption ◽  
Solid Liquid Interface ◽  
Solid Liquid

The main objective of this work is to study the mathematical modeling of the adsorption of Co2+ ions on sugarcane bagasse (SCB) for approximate the nature of the adsorption. The together of results obtained show that the adsorption process is favorable for a chemisorption and monolayer. Also, the adsorption process is expressed by the second order kinetic law. Thus the negative values of ΔG° and the positive values of ΔH° opt for an endothermic and spontaneous process. Also, the positive values of ΔS° indicate the increase in the randomness at the solid / liquid interface during the adsorption of the Co2+ metal ions.

Competitive transport of cadmium and lead through a natural porous medium: influence of the solid/liquid interface processes

2003 ◽  
Vol 48 (3) ◽  
pp. 9-16 ◽  
Author(s):  
A. Bianchi ◽  
M. Petrangeli Papini ◽  
A. Corsi ◽  
P. Behra ◽  
M. Beccari
Keyword(s):  
Liquid Interface ◽  
Equilibrium Adsorption ◽  
Adsorption Model ◽  
Adsorption Sites ◽  
Advection Dispersion ◽  
Transport Behaviour ◽  
Cadmium And Lead ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Medium Influence

Contaminated groundwater typically contains different metal contaminants which may compete with each other for the same adsorption sites. Understanding the fate of these micro-pollutants is of primary importance for the assessment of the risk associated with their dispersion in the environment and for the evaluation of the most appropriate remediation technology. In this regard, column techniques can be considered as useful tools both to perform transport experiments and to obtain equilibrium adsorption data without any perturbation of the actual solid/liquid interface. Cd and Pb monocomponent step column experiments were used to obtain adsorption isotherms on a natural aquifer material. A General Composite approach was used to define the equilibrium adsorption model characterized by two types of sites (ion-exchange and surface complexation sites). Coupling the adsorption model with the Advection-Dispersion equation (by IMPACT code) allowed us to well represent the monocomponent step experiments. The model was successfully used to predict the competitive Cd and Pb transport behaviour. Cd peaks of concentration due to Pb competition were experimentally observed and simulated by the model. This behaviour can be described only by an accurate modelling of the interaction and cannot be predicted by simple isotherms (such as Langmuir or Freundlich type).

scholarly journals Continuous-Mode Laser Ablation at the Solid–Liquid Interface of Pelletized Low-Cost Materials for the Production of Luminescent Silicon Carbide Nanocrystals

2015 ◽  
Vol 119 (4) ◽  
pp. 2158-2165 ◽  
Author(s):  
M. Carmen Ortega-Liébana ◽  
José L. Hueso ◽  
Raul Arenal ◽  
Ruth Lahoz ◽  
Germán F. de la Fuente ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Laser Ablation ◽  
Low Cost ◽  
Liquid Interface ◽  
Continuous Mode ◽  
Mode Laser ◽  
Solid Liquid Interface ◽  
Solid Liquid

Comparison of the fixation of several metal ions onto a low-cost biopolymer

2002 ◽  
Vol 2 (5-6) ◽  
pp. 217-224 ◽  
Author(s):  
Z. Reddad ◽  
C. Gérente ◽  
Y. Andrès ◽  
P. Le Cloirec
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Low Cost ◽  
Operating Conditions ◽  
Order Kinetic ◽  
Adsorption Mechanisms ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Beet Pulp ◽  
Removal Of Metal Ions

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ > Cd2+ > Zn2+ > Cu2+ > Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.

Observation of Femtosecond Acoustic Anomaly in a Solid Liquid Interface

2020 ◽  
Vol 124 (5) ◽  
pp. 2987-2993
Author(s):  
Chi-Kuang Sun ◽  
Yi-Ting Yao ◽  
Chih-Chiang Shen ◽  
Mu-Han Ho ◽  
Tien-Chang Lu ◽  
...  
Keyword(s):  
Liquid Interface ◽  
Acoustic Anomaly ◽  
Solid Liquid Interface ◽  
Solid Liquid
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