Influence of interfering anions on Cu2+ and Zn2+ ions removal on chestnut outer shell-derived hydrochars in aqueous solution

Hydrothermal carbonization method was used to produce different hydrochars from chestnut outer shell at various temperatures while resolving the environmental issues of agricultural bio-waste. Hydrochars were adopted as adsorbents to remove heavy metal ions (copper and zinc ions) from aqueous solution. Hydrochar samples were characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption isotherm. An increase in the hydrothermal temperature from 160 °C to 220 °C results in higher BET surface area (18.81 m2 g-1) and the porosity of the samples. The resultant hydrochar at 220 °C exhibited a more excellent adsorption performance (8.13 mg g-1 for copper nitrate) than the other two hydrochars at low hydrothermal temperature. The current study addressed the influence of interfering anions of nitrates, sulfates and chlorides on the adsorption performance. The result shows that the hydrochar possesses larger removal efficiency for heavy metal nitrates that that of chlorides and sulfates

Adsorption of alpha-Picoline and gamma-Picoline on the Adsorbent Produced from Spent Bleaching Earth

Adsorbents were produced from spent bleaching earth and the individual adsorption of alpha-picoline and gamma-picoline by them was studied as a function of time, pH and initial concentration. The adsorption process for both solutes followed the first order Lagergren equation and the rate constants of the adsorption were calculated for each solute. Rate constants of intraparticle diffusion were also calculated for each solute. The adsorption capacities were obtained from the Langmuir isotherm. In order to understand adsorption mechanism, Giles isotherm was used and adsorption type for each solute was determined. Maximum adsorption capacity was observed between pH: 8.13 and 8.77

Equilibrium, kinetic and mass transfer studies and column operations for the removal of arsenic(III) from aqueous solutions using acid treated spent bleaching earth

In the present study, a new adsorbent was produced from spent bleaching earth by H2SO4 impregnation method. The sorption of arsenic(III) by acid treated spent bleaching earth was studied to examine the possibility of utilizing this material in water treatment systems. The effect of time, pH, initial concentration, temperature on the adsorption of arsenic(III) was studied. Maximum adsorption was found to occur at pH 9.0. The adsorption process followed the first order Lagergren equation. Mass transfer coefficients and rate constants of intraparticle diffusion were calculated. The experimental data points were fitted to the Langmuir equation in order to calculate the adsorption capacity (Q) of the adsorbent and the value of Q(0) was found to be 0.46 mmol g(-1). In order to understand the adsorption mechanism, Dubinin-Radushkevich (DR) isotherm was used. The magnitude of E calculated from DR equation was found to be 5.12 kJ mol(-1). The heat of adsorption (DeltaH(o) = -30367 J mol(-1)) implied that the adsorption was physical exothermic adsorption. The column studies were also carried out to simulate water treatment processes. The capacity values obtained in column studies were found to be greater than the capacity values obtained in batch studies. This result was explained by the difference between batch system and column stem. The factors that affect the capacity values of column and batch systems were explained. The effect of other anions on e adsorption of arsenic(III) in the presence of NO3-, SO4-, Cl-, Br- was studied. The presence of these anions did not affect the adsorption of arsenic(III) significantly

2,4 D adsorption by the adsorbents produced from contaminated soil

The waste material from a gaswork site was converted into low cost adsorbents by physical and chemical methods and utilized for the adsorption of 2,4 - D (2,4-dichlorophenoxy acetic acid). Chemical activation method was found to be more effective than physical method, as confirmed by surface area and porosity data. In the batch experiments, some parameters such as contact time, adsorbent concentration, and temperature were studied. Kinetic studies were made using the first order equation. The equilibrium data fit well to the Langmuir and Freundlich models. Thermodynamic parameters were calculated and these values showed that adsorption process was exothermic and favoured at low temperatures

Removal of MCPA (4-chloro-2-methylphenoxy-acetic acid) from aqueous solutions using adsorbent produced from elutrilithe

Elutrilithe is a mixed alumina-silicate/carbon material and a solid waste of coal mines. In this study we tried to produce a new adsorbent from elutrilithe. The elutrilithe was treated with zinc chloride in an N-2 medium. The adsorption capacity of the new adsorbent was measured with MCPA (4-chloro-2-methylphenoxy-acetic acid), which is a pesticide

Removal of Phenolic Substances from Water by Adsorption and Adsorption-Ultrafiltration

In this work a magnetic adsorbent, magnetic activated carbon (MAC) was prepared and characterized by powdered X-Ray diffraction (XRD). A comparison was made between powdered activated carbon (PAC) and MAC for foul control in ultrafiltration (UF) membrane processes. First, the adsorptive parameters for PAC and MAC were determined for phenol, chlorophenol, nitrophenol, and hydroquinone. Equilibrium data fitted well to the Langmuir model in the studied concentration range of the adsorbates. Adsorption kinetics followed a pseudo second-order kinetic model rather than pseudo first-order kinetic model. These adsorbents were then used in combination with UF membrane. The parameters like percent rejection and flow rate for the hybrid UF/PAC and UF/MAC were determined. The influences of both adsorbents on flow rates and percent rejections were almost equal. The problems associated with PAC in the UF processes like cake formation and blackening of the pipes were not observed for MAC. MAC was removed from the slurry after use through a magnetic process

Adsorption of beta-picoline on the adsorbents produced from spent bleaching earth

The sorption of beta-picoline by acid treated spent bleaching earth was studied to examine the potentiality of this material in treatment systems. The effect of time, pH, initial concentration on the adsorption of beta-picoline was studied. Lagergren first order rate equation was used to describe the adsorption rate of beta-picoline and adsorption rate constants were calculated. Rate constants of intraparticle diffusion were calculated. Adsorption isotherms were modelled by the Langmuir equation and the isotherm constants of this isotherm were calculated. The dependence of the adsorption of P-picoline on the pH of the solution was studied to achieve the optimum pH value and a better understanding of the adsorption mechanism. The maximum adsorption was found to occur at pH 7.85. Giles isotherm was used and adsorption type was determined