Considering general trend of energy consumption, according to which the amount of consumed energy increases, its cost and scarcity continuously increase. The 10–12 % of all energy is spent on drying processes in the world. At the current stage of the development of dehydration processes in Ukraine and the world, an urgent problem has arisen in the creation and development of highly efficient thermal technologies that would ensure minimal energy consumption for the process and high quality of the material.
The adsorption of nucleotides on the surface of nanocrystalline cerium dioxide (pHpzc = 6.3) in NaCl solutions was investigated using multi-batch adsorption experiments over a wide range of pH. The obtained results were interpreted as a formation of outer and inner sphere surface complexes with the participation of phosphate moieties. The Basic Stern surface complexation model was applied to obtain quantitative equilibrium reaction constants.
Chemical composition of sugar cane vinasse (Tucumán, Argentina) was studied finding high concentration of organic compounds. Phenolic compounds were partially characterized, finding mostly flavonoids, anthocyanins, as well as resorcinol and ferulic acid derivatives. Adsorption isotherms of phenolic compounds and total organic compounds were measured on four commercial activated carbons with different physical and chemical properties at two temperatures. The isotherm shape depends on the type of carbon and the adsorption capacity is enhanced as temperature increases.
To selectively remove mercury(II), 2-hydroxyethyl methacrylate (HM) and 2-hydroxyethyl methacrylate/acrylamide (HM/ACR) hydrogels were synthesized using radiation. These hydrogels were used in swelling, diffusion, and binding studies. Swelling parameters for HM/ACR−Hg2+ system are higher than those of HM−Hg2+ systems. Binding of Hg2+ has been observed to be C-type for HM and L-type for HM/ACR hydrogels. Binding parameters were calculated using Freundlich, Langmuir and Henry models.
The paper presents the results of the study of the statics of adsorption of surface-active substances from model solutions by activated carbon and zeolite. The results of photometric determination of the concentration of anionic surfactants before and after adsorption are presented. The results of adsorption capacity calculations are presented. The experimental results using the program (Langmuir 1.03) were numerically calculated. Sorption isotherms of sodium dodecyl sulfate indicate the mechanism of monomolecular physical adsorption.
The dynamics of the adsorption process in the fixed-bed column was experimentally studied on the example of the system natural zeolite - water solution of copper salt with low concentrations, which are characteristic for wastewater treatment processes from toxic contaminants. The initial curves of the adsorption process for the height of the sorbent layer of 5 and 7 cm were constructed. The equilibrium of such processes can be described by Henry's linear equation. The adsorption process in the layer consists of two stages, which are examined in the study.
Chelating resin as a new copolymer for metal ions removal was prepared using 3-(4-hydroxyphenyl) cyclopropane-1,1,2,2-tetracarboxylic acid and 1,2-diaminoethane on the poly(styrene-alt-maleic anhydride). Parameters of sorption behavior were investigated under various conditions. Kinetics studies revealed that the adsorption process confirmed the pseudo-second-order kinetics and adsorption data were well fitted to Langmuir isotherm.
This paper describes the adsorption of Cu2+ and Fe2+ ions, common heavy metals found in industrial wastewater, by a fly ash-based geopolymer in batch adsorption experiments. Kinetics studies showed that the adsorption of each ion followed a pseudo-second order reaction. Moreover, adsorption isotherm of Cu2+ and Fe2+ ions followed the Langmuir model. Monolayer adsorption capacities were approximately 53.76 mg/g for Cu2+ ion and 52.63 mg/g for Fe2+ ion, respectively.
The current study deals with the removal of cationic dye (brilliant green) and anionic dye (methyl orange) from wastewater by using sunflower husk as an adsorbent. The operation takes place batch wise by applying several concentrations of the dye solution with various adsorbent amounts, at a range of initial PH values and particle sizes at varying contact time intervals. The percent of dye removed for two dyes increased with increasing time and adsorbent dose and decreased with increasing the dye concentration and particle size. The equilibrium time differed according to conditions used.
The efficiency of surface modified nanoscale zerovalent iron (nZVI) composite by cashew nut shell (CNS) was tested for the removal of cadmium ions from the aqueous solutions. 2 g/l CNS-nZVI was efficient for 98% removal. The adsorption capacity was 35.58 mg/g. The Freundlich isotherm (R2= 0.9769) and the pseudo-second order adsorption kinetics data fitted well. This proved CNS-nZVI has a high removal efficiency for Cd(II) from aqueous solutions.