Adsorbent phosphates

An adsorbent which uses as its primary ingredient phosphoric acid salts of zirconium or titanium is presented. Production methods are discussed and several examples are detailed. Measurements of separating characteristics of some gases using the salts are given

Adsorption-induced surface normal relaxation of a solid adsorbent

We investigate adsorption of a gas on the flat surface of a solid deformable adsorbent taking into account thermal fluctuations and analyze in detail the effect of thermal fluctuations on the adsorbent deformation in adsorption. The condition for coexistence of two states of a bistable system of adsorbed particles is derived. We establish the specific properties of the adsorption-induced surface normal relaxation of an adsorbent caused by thermal fluctuations. The mean transition times between two stable states of the bistable system are derived in the parabolic approximation and in the general case.Comment: 16 pages, 5 figure

Rapid removal of phenol from aqueous solutions by AC_Fe3O4 nano-composite: Kinetics and equilibrium studies

Background and purpose: Phenol and its derivatives are used as raw material in many chemical, pharmaceutical and petrochemical industries. It is classified as priority pollutant, due to its high toxicity. In this study, the magnetic activated carbon nano-composite was used for quick removal of phenol. Materials and methods: The activated carbon was modified by magnetic nano-particles. Then physical properties of the adsorbent were investigated using BET, XRD and SEM. Afterwards, adsorption behavior of phenol onto the adsorbent was studied considering various parameters such as: pH, phenol concentration, contact time and adsorbent dosage. Also, the isotherms and adsorption kinetics model was studied. Results: BET analysis showed 10.25% decrease in the specific area of activated carbon after being amended by the Fe3O4 nano-particles. SEM and XRD confirmed the presence of Fe3O4 nanoparticles on the activated carbon. Optimum absorption points in this process were pH=8, contact time of 15 min and adsorbent dose 2 g/L. The Longmuir isotherm and pseudo-second-order kinetics were fitted to the data. The maximum adsorption capacity of phenol on AC_Fe3O4 was 84.033 mg/g. Conclusion: Creating magnetic properties on the activated carbon which has a high adsorption capacity of phenol could result in quick separation of phenol from aqueous solutions. Also, this adsorbent could be widely applied since it is inexpensive and simple to use. © 2015, Mazandaran University of Medical Sciences. All rights reserved

Optimization of biosorption process using cucumis melo rind for the removal of Fe, Mn and Pb ions from groundwater

Biosorption can be an effective technique for the treatment of metal-bearing groundwater. Several fruits and agricultural by-products demonstrated the ability to remove the heavy metals and thereby reduce the water contaminants. In the present study, the potential use of biosorbent material obtained from Cucumis melo rind for the removal of Pb, Fe and Mn ions from groundwater was investigated according to four types of parameters namely pH, biosorbent dosage, initial metal concentration and contact time. Characterization of biosorbent was done by the means of SEM-EDX, XRF and FTIR analysis to observe for the surface morphology, elemental composition and functional groups available on the biosorbent. Sorption was most efficient at pH 7 for Fe(II) and pH 6.5 for both Mn(II) and Pb(II) using 0.05g/100ml biosorbent dosage at contact time of 45 minutes. The biosorption of all metals increased with increasing biosorbent dosage. FTIR study revealed the presence of functional groups on the surface of biosorbent facilitates the biosorption of the metal ions. The Langmuir, Freundlich and BET isotherm models were used to predict the behavior metal binding while Langergren Pseudo-first and Pseudo-second order were used to study the kinetics aspects. The equilibrium data for all metals were best fit to the Langmuir adsorption isotherm with maximum adsorption capacity of 5.3505 mg/g, 2.7525 mg/g and 0.0830 mg/g respectively for Fe(II), Mn(II) and Pb(II). The result indicates that the Pseudo-second order model best describes the kinetics data. The Cucumis melo rind successfully removes up to 90.73%, 91.47% and 90.94% respectively to Fe, Mn and Pb in the groundwater samples which reduce the metals level below the WHO recommended limits of heavy metal for drinking water

Superior removal of arsenic from water with zirconium metal-organic framework UiO-66

10.1038/srep16613Scientific Reports51661

Optimal design of gas adsorption refrigerators for cryogenic cooling

The design of gas adsorption refrigerators used for cryogenic cooling in the temperature range of 4K to 120K was examined. The functional relationships among the power requirement for the refrigerator, the system mass, the cycle time and the operating conditions were derived. It was found that the precool temperature, the temperature dependent heat capacities and thermal conductivities, and pressure and temperature variations in the compressors have important impacts on the cooling performance. Optimal designs based on a minimum power criterion were performed for four different gas adsorption refrigerators and a multistage system. It is concluded that the estimates of the power required and the system mass are within manageable limits in various spacecraft environments

Cobalt removal from wastewater using pine sawdust

Agricultural wastes can cause environmental problems if not well managed, but there is a lot of potential to use these wastes as raw material in other processes. In this investigation, pine sawdust was evaluated as an adsorbent in the treatment of wastewater containing cobalt ions. A two-level three-factor full-factorial experimental design with centre points was used to study the interactive effect of the operating parameters in order to achieve the best conditions for the batch adsorption of cobalt ions. A response surface analysis was also conducted to further understand the interactions amongst the factors such as adsorbent dose, solution pH and initial concentration. In addition, adsorption isotherms, namely the Freundlich and Langmuir, were used to characterize the removal of cobalt from the wastewater. It was observed that the combined effect of low adsorbent dose, high pH and high initial concentration of wastewater resulted in the highest adsorption capacity. The Freundlich isotherm provided a better fit to the experimental data than the Langmuir isotherm. Moreover, pine sawdust showed adsorption capabilities for cobalt, and hence it could be an option in the quest to use waste to treat wastewater

Preparation and characterisation of irradiated waste eggshells as oil adsorbent

Adsorption method had been developed by using natural organic adsorbent for the removal of oil because of its ability to bind the oil molecules into the surface of adsorbent. In this study, chicken eggshells waste was used and it undergoes irradiation process with four different amount of dose which was 0.5 kGy, 1.0 kGy, 1.5 kGy, and 2.0 kGy by using Gamma Cell Irradiator. Three equipment had been used for the characterization process which were the Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX), and Fourier-Transform Infrared Spectroscopy (FTIR). The adsorption experiment was conducted to calculate the sorption efficiency by using different mass of samples. The result showed that irradiated chicken eggshells powder with 2.0 kGy amount of radiation dose has a best performance as oil adsorbent

In silico simulation of blood glucose-insulin dynamics using MATLAB-Simulink

Diabetes mellitus (DM) is a major public health concern in Malaysia and it continuously increases over years. Based on International Diabetes Federation, there are rising numbers of people having diabetes with 3.6 million people in Malaysia and 463 million people in the world [1]. The National Health and Morbidity Survey (NHMS) 2019 has shown that the diabetes in Malaysia has increased from 13.4% in 2015 to 18.3% in 2019 [2]. This can significantly increase the cost in diabetes treatment and management