Aqueous phase adsorption of organic/inorganic contaminants by eucalyptus bark (eucalyptus sheathiana) biomass

This research demonstrates the adsorption characteristics of raw and chemically treated eucalyptus bark (Eucalyptus sheathiana) biomass as a cost effective agricultural solid waste adsorbent in the removal of organic/inorganic contaminants from their aqueous phase. Mechanism of adsorption and identification of various process parameters and their optimum values have been explored here. The research outcomes are to show large potential of eucalyptus bark to treat dye and metal bearing wastewaters alternative to many costly commercial adsorbents

Equilibrium, Kinetics and Mechanism of Removal of Methylene Blue from Aqueous Solution by Adsorption onto Pine Cone Biomass of Pinus radiata

The kinetics and mechanism of methylene blue adsorption onto raw pine cone biomass (Pinus radiata) was investigated under various physicochemical parameters. The extent of the methylene blue dye adsorption increased with increases in initial dye concentration, contact time and solution pH but decreases with the amount of adsorbent, salt concentration and temperature of the system. Overall the kinetic studies showed that the methylene blue adsorption process followed pseudo-second-order kinetics among various kinetic models tested. The different kinetic parameters including rate constant, half-adsorption time and diffusion coefficient are determined at different physicochemical conditions. Equilibrium data were best represented by Langmuir isotherm among Langmuir and Freundlich adsorption isotherm. The maximum monolayer adsorption capacity of pine cone biomass was 109.89 mg/g at 30°C. The value of separation factor, R L, from Langmuir equation and Freundlich constant, n, both give an indication of favourable adsorption. Thermodynamic parameters such as standard Gibbs free energy (∆G 0), standard enthalpy (∆H 0), standard entropy (∆S 0) and the activation energy (A) were calculated. A single-stage batch absorber design for the methylene blue adsorption onto pine cone biomass has been presented based on the Langmuir isotherm model equation

Agricultural solid wastes in aqueous phase dye adsorption: A Review

Wastewater from many industries such as textile, leather, paper, printing, food, etc. contains large amount of hazardous dyes. Dyes are not biodegradable and photodegradable due to its synthetic origin and complex aromatic nature. Among various physiochemical processes, adsorption techniques are usually widely used to treat dyes laden wastewater. Although commercial activated carbon is the most widely used adsorbent with large success, its use is limited due to high cost and difficulties in regeneration. Therefore there have been explosive growths in research concerning the use of alternative cost effective non-conventional effective adsorbents in the removal of dyes from aqueous solution. In this research direction, agricultural by-product solid wastes which are available in large quantities worldwide with almost through away price are utilized as effective adsorbents in the removal of inorganics and organics from wastewater. The focus of this book chapter is to review extensive literature information about dyes, its classification and toxicity, various treatment methods and finally dye adsorption characteristics by various agricultural by-products solid wastes as adsorbents. The major objective of this chapter is to organize the scattered available information on the adsorptive removal of dyes from its aqueous solution by raw and treated agricultural by-products. Selectively widely used agricultural solid waste adsorbents in the removal of dyes have also been discussed in details here. Finally mechanism, kinetics and adsorptive behaviour of adsorbents under various physicochemical process parameters have been critically analysed and compared. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed

Adsorption removal of zinc (II) from aqueous phase by raw and base modified Eucalyptus sheathiana bark: Kinetics, mechanism and equilibrium study

In this study, potential application of abundantly available agricultural by-product Eucalyptus sheathiana bark in its raw and sodium hydroxide (NaOH) modified form to remove Zn2+ from its aqueous solutions was investigated by considering parameter identification and optimization, reusability, equilibrium, kinetic and thermodynamic studies. The adsorbent was characterized by SEM-EDX, FTIR, XRD, BET surface area and bulk density and point of zero charge were also determined. The process was strongly pH dependent and the adsorption percentage of Zn2+ was increased with an increase in solution pH from 2.5 to 5.1. Conversely, the adsorption percentage of Zn2+ decreased with the increase in adsorbent dosage, initial metal concentration, temperature and ionic strength. Kinetic measurements showed that the process was multistep, rapid and diffusion controlled. It was found to follow the pseudo-second-order rate equation. Equilibrium adsorption studies showed that both Freundlich and Langmuir models are applicable for both raw and base modified eucalyptus bark. MPSD error function was used to treat the equilibrium data using non-linear optimization technique for evaluating the fit of the isotherm equations. The maximum sorption capacity of modified eucalyptus bark was 250.00 mg/g at 30 °C which was comparative to other adsorbents. Various thermodynamic parameters indicate that the process was spontaneous and physical in nature. Desorption studies were also performed to determine possible recovery potential of Zn2+ and the re-usability of the biomass and to identify the mechanism of adsorption

Fixed-bed dynamic column adsorption study of methylene blue (MB) onto pine cone

The effectiveness of pine cone biomass in the removal of methylene blue (MB) dye from its aqueous solution was tested here by a fixed-bed column adsorption study. The adsorption column breakthrough curves (BTCs) indicated the favourable column dynamics and its dye adsorptive behaviour depends on feed flow rate, initial MB dye concentration and column bed height. The results showed that the amount of total sorbed dye, equilibrium dye uptake, mass transfer zone and total percentage of dye removal increased with increase in MB dye concentration and the height of the bed, but decreased with increase in initial flow rate. To determine the fixed-bed column adsorption kinetic parameters, Thomas, Yoon–Nelson and Bed Depth Service Time (BDST) models fitted the experimental BTC obtained from dynamic studies. All these parameters are required for the design of adsorption column and it was found that all three kinetic models were applicable.Thomas model showed that the value of maximum solid-phase concentration (q0) decreased when the flow rate and the height of the bed increased but increased with increasing initial MB dye concentration. The value of Thomas kinetic rate constant (KTh) increased with higher flow rate but decreased with increasing initial MB dye concentration and the height of the bed. Yoon–Nelson model showed that the time required to achieve 50% adsorbate breakthrough, τ fitted well with the experimental data (τ50% exp.) in the entire column adsorption system. The rate constant KYN increased with both increasing flow rate and initial MB dye concentration but decreased with increasing bed height. The BDST model showed that the rate constant (K0) decreased when both the bed heights and the initial MB dye concentration increased, but increased with the increase in flow rate. The value of the volumetric sorption capacity of the bed (N0) increased with increasing flow rate, initial MB dye concentration and bed height. Overall, all the three models were fitted well with the experimental data

Removal of anionic surfactant sodium dodecyl sulphate from aqueous solution by adsorption onto pine cone biomass of Pinus Radiate: equilibrium, thermodynamic, kinetics, mechanism and process design

This study was undertaken to evaluate the adsorption potential of a natural, low-cost agricultural by-product adsorbent, Pine cone (Pinus Radiate), to remove sodium dodecylsulfate (SDS) from aqueous solution. It was found that the extent of SDS adsorption by pine cone biomass increased with initial surfactant concentration and contact time but decreased with increasing solution pH, amount of adsorbent, and temperature of the system. These studies also suggested that the electrostatic forces and surfactant self-assembly are dominant mechanisms governing this pH dependent adsorption process. Overall, kinetic studies showed that the surfactant adsorption process followed pseudo-second-order kinetics based on pseudo-first-order and intraparticle diffusion models. The different kinetic parameters including rate constant, half adsorption time, and diffusion coefficient were determined at different physicochemical conditions. Equilibrium data were fitted by both the Langmuir isotherm and Freundlich adsorption isotherm. The maximum monolayer adsorption capacity of pine cone biomass was 95.75 mg g−1 at 20°C. The value of separation factor, R L from Langmuir equation and “n” from Freundlich also indicated favourable adsorption. Thermodynamic parameters such as ΔG 0, ΔH 0, and ΔS 0 were calculated. A single-stage batch absorber design for the SDS adsorption onto pine cone biomass also presented based on the Freundlich isotherm model equation

Adsorption of methylene blue dye from aqueous solution by novel biomass Eucalyptus sheathiana bark: equilibrium, kinetics, thermodynamics and mechanism

This study was undertaken to evaluate the adsorption potential of a naturally available, cost-effective, raw eucalyptus bark (EB) (Eucalyptus sheathiana) biomass, to remove organic methylene blue (MB) dye from its aqueous solutions. Effects of various process parameters such as initial dye concentration, adsorbent loading, solution pH, temperature, presence of salts, mixture of dyes and surfactant onto MB dye adsorption by bark material were studied. Significant effect on adsorption was witnessed on varying the pH of the MB solutions. Results showed that the optimum pH lies between 7.4 and 10.0. The extent (%) of MB adsorption from aqueous solution decreased with the increase in the initial MB dye concentration, but increased with rise in temperature. The extent of MB dye adsorption was found to be enhanced due to increase of salts concentration. This is because of salting-out-effect, which comprises the changes of various short range forces.The overall kinetic studies showed that the MB dye adsorption by EB biomass followed pseudo-second-order kinetics. The mechanism of MB dye adsorption was analysed by intra-particle diffusion model and desorption study. Free energy change of adsorption (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) were calculated to predict the nature of adsorption. The Langmuir adsorption isotherm model yields a better correlation coefficient than the Freundlich model and the dimensionless separation factor “RL” indicated favourable adsorption process. The maximum Langmuir monolayer adsorption capacity of raw EB for MB dye was found to be 204.08 mg/g at 30°C. A single-stage batch adsorber design for MB dye adsorption onto EB biomass has been presented based on the Langmuir isotherm model equation. The results obtained in this study suggest a promising future for inexpensive raw EB biomass as a novel adsorbent and a better alternative to activated carbon adsorbent used for the removal of MB dye from dye bearing effluents

Adsorption performance of continuous fixed bed column for the removal of methylene blue (MB) dye using Eucalyptus sheathiana bark biomass

In this study, the adsorptive effectiveness of sustainable and cost-effective eucalyptus bark biomass in the removal of methylene blue (MB) dye from its aqueous solution has been tested using a packed bed up-flow column experiment. A series of column experiments using raw eucalyptus bark was performed to determine the breakthrough curves with varying inlet MB dye flow rate (10–15 mL min−1), initial MB dye concentration (50–100 mg L−1) and adsorbent bed height (10–15 cm). High bed height, low flow rate and high initial dye concentration were found to be the better conditions for maximum dye adsorption. To predict the breakthrough curves and to determine the characteristic parameters of the column dynamics for industrial applications and for process design, Thomas model, Yoon–Nelson model and bed depth service time model were applied to experimental breakthrough data. All models were found suitable for describing the dynamic behaviour of the column, with respect to MB flow rate, initial dye concentration and adsorbent bed height. The findings revealed that eucalyptus bark biomass has a high adsorption potential for the removal of MB dye from aqueous solutions in a column system, and that it could be used to treat dye-containing effluents

Dye and its removal from aqueous solution by adsorption: A review

In this review article the authors presented up to-date development on the application of adsorption in the removal of dyes from aqueous solution. This review article provides extensive literature information about dyes, its classification and toxicity, various treatment methods, and dye adsorption characteristics by various adsorbents. One of the objectives of this review article is to organise the scattered available information on various aspects on a wide range of potentially effective adsorbents in the removal of dyes. Therefore, an extensive list of various adsorbents such as natural materials, waste materials from industry, agricultural by-products, and biomass based activated carbon in the removal of various dyes has been compiled here. Dye bearing waste treatment by adsorption using low cost alternative adsorbent is a demanding area as it has double benefits i.e. water treatment and waste management. Further, activated carbon from biomass has the advantage of offering an effected low cost replacement for non-renewable coal based granular activated carbon provided that they have similar or better adsorption on efficiency. The effectiveness of various adsorbents under different physico-chemical process parameters and their comparative adsorption capacity towards dye adsorption has also been presented. This review paper also includes the affective adsorption factors of dye such as solution pH, initial dye concentration, adsorbent dosage, and temperature. The applicability of various adsorption kinetic models and isotherm models for dye removal by wide range of adsorbents is also reported here. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed