Removal of Heavy Metals from Aqueous Media by Ion Exchange with Y Zeolites

Author(s):  
Mark Keane
2016 ◽  
Vol 14 (1) ◽  
pp. 175-187 ◽  
Author(s):  
Lăcrămioara (Negrilă) Nemeş ◽  
Laura Bulgariu

AbstractMustard waste biomass was tested as a biosorbent for the removal of Pb(II), Zn(II) and Cd(II) from aqueous solution. This strategy may be a sustainable option for the utilization of such wastes. The influence of the most important operating parameters of the biosorption process was analyzed in batch experiments, and optimal conditions were found to include initial solution pH 5.5, 5.0 g biosorbent/L, 2 hours of contact time and high temperature. Kinetics analyses show that the maximum of biosorption was quickly reached and could be described by a pseudo-second order kinetic model. The equilibrium data were well fitted by the Langmuir model, and the highest values of maximum biosorption capacity were obtained with Pb(II), followed by Zn(II) and Cd(II). The thermodynamic parameters of the biosorption process (ΔG, ΔH and ΔS) were also evaluated from isotherms. The results of this study suggest that mustard waste biomass can be used for the removal of heavy metals from aqueous media.


2018 ◽  
Vol 77 (10) ◽  
pp. 2355-2368 ◽  
Author(s):  
Khalida Naseem ◽  
Zahoor H. Farooqi ◽  
Muhammad Z. Ur Rehman ◽  
Muhammad A. Ur Rehman ◽  
Robina Begum ◽  
...  

Abstract This review is based on the adsorption characteristics of sorghum (Sorghum bicolor) for removal of heavy metals from aqueous media. Different parameters like pH, temperature of the medium, sorghum concentration, sorghum particle size, contact time, stirring speed and heavy metal concentration control the adsorption efficiency of sorghum biomass for heavy metal ions. Sorghum biomass showed maximum efficiency for removal of heavy metal ions in the pH range of 5 to 6. It is an agricultural waste and is regarded as the cheapest biosorbent, having high adsorption capacity for heavy metals as compared to other reported adsorbents, for the treatment of heavy metal polluted wastewater. Adsorption of heavy metal ions onto sorghum biomass follows pseudo second order kinetics. Best fitted adsorption isotherm models for removal of heavy metal ions on sorghum biomass are Langmuir and Freundlich adsorption isotherm models. Thermodynamic aspects of heavy metal ions adsorption onto sorghum biomass have also been elaborated in this review article. How adsorption efficiency of sorghum biomass can be improved by different physical and chemical treatments in future has also been elaborated. This review article will be highly useful for researchers working in the field of water treatment via biosorption processing. The quantitative demonstrated efficiency of sorghum biomass for various heavy metal ions has also been highlighted in different sections of this review article.


Author(s):  
V. Kofman

Микродвигатели представляют собой автономные, выполняющие определенные функции самодвижущиеся микроустройства на основе неорганических, органических или биологических материалов. В конструкции микродвигателя реализованы две функции: автономное движение и эффективный захват и/или деструкция различных химических веществ, в том числе загрязняющих. Для обеспечения автономного движения устройство микродвигателей предусматривает создание локальных термических, акустических, химических градиентов, проистекающих из ассиметричной морфологии или поверхностной структуры. Движение обеспечивается за счет использования различных источников энергии, включая свет, электрические и магнитные поля, ультразвуковые волны или химическое топливо . Хаотичная траектория движения микродвигателей в объеме раствора обеспечивает высокоэффективное взаимодействие иммобилизованных на их поверхности реагентов с целевыми загрязняющими или детектируемыми веществами. Наиболее проработанный принцип создания автономного движения заключается в возникновении импульса отдачи при ассиметричном образовании в результате химической реакции газовых микропузырей. В настоящее время основные исследования применения микродвигателей в процессах водоочистки проводятся по направлениям анализа водных сред, удаления тяжелых металлов, органических загрязняющих веществ, красителей и нефтепродуктов, а также обеззараживания воды. По оценкам, микродвигателям присущи уникальные возможности в области детектирования и удаления загрязняющих веществ в водной среде вследствие сочетания адсорбционных и каталитических свойств с автономным перемещением.Micromotors are autonomous, performing certain functions, selfpropelled microdevices based on inorganic, organic or biological materials. Implemented in a micromotor design are two functions: autonomous movement and effective capture and/or destruction of various chemicals, including pollutants. To ensure autonomous movement the micromotor device provides for the creation of local thermal, acoustic, chemical gradients arising from asymmetric morphology or surface structure. The movement is provided through the use of various energy sources including light, electric and magnetic fields, ultrasonic waves or chemical fuel. The chaotic trajectory of micromotors throughout the solution provides for the highly efficient interaction of the chemicals immobilized on their surface with the targeted pollutants or detectable substances. The most elaborated principle of creating autonomous movement is the generation of a recoil impulse at asymmetric formation of gas microbubbles as a result of a chemical reaction. Currently, the main studies on the use of micromotors in water purification processes are carried out in the areas of analysis of aqueous media, removal of heavy metals, organic pollutants, dyes and oil products, as well as water disinfection. It is estimated that micromotors possess unique capabilities in the field of detection and removal of pollutants in aqueous media due to a combination of adsorption and catalytic properties with autonomous movement.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Supitcha Rungrodnimitchai

This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (∼3.62 meq/g) and shorter reaction time (1.5–5.0 min) than the phosphorylation by oil bath heating. Adsorption experiments towards Pb2+, Cd2+, and Cr3+ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40 ppm, adsorbent 2.0 g/L). The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax). As a result of Pb2+sorption test, the modified rice straw (RH-NaOH 450W) removed Pb2+much faster in the initial step and reached 92% removal after 20 min, while Dowax (commercial ion exchange resin) took 90 min for the same removal efficiency.


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