Investigation of Strontium (II) Sorption Kinetic and Thermodynamic onto Straw-derived Biochar

Abstract

Biochars have attracted much research attention recently because of their potential applications in many environmental areas. In this study, rice straw-derived biochars produced at different pyrolysis temperatures (550-750 C) were used as adsorbents for the removal of strontium (II) under different experimental conditions of time, pH, and temperature. Sr(II) sorption equilibrium occurs after 30 min and its sorption maximum achieved at pH 6. The kinetic data obtained were analyzed to predict the constant rate of sorption using three common kinetic models: pseudo-first-order, pseudo-second-order equation, and intraparticle diffusion equation. The pseudo-second-order model was suitable for describing the sorption kinetics for the removal of Sr(II) from aqueous solution onto straw-derived biochar. Sorption of Sr(II) onto biochar was endothermic. Biochar has the highest Sr(II) sorption capacity in comparison to other adsorbents.

Controlled bi-functionalization of silica microbeads through grafting of amidoxime/methacrylic acid for Sr(II) enhanced sorption

“…This is a confirmation that the resistance to intraparticle diffusion plays a role in the control of the up take kinetics. These values are about one order of magnitude lower than the values rep orted for diffusivity o f S r(II) in sorbent based on titanium phosphate (i.e., 6 × 10 −10 m 2 min −1 ) [91] but several orders of magnitude higher than the effective diffusivity of Sr(II) into straw-derived char (5.4 × 10 −14 m 2 min −1 ) [92]. For macroporous resin, Sr(II) diffusivity was evaluated close to 1.2 × 1 0 −8 m 2 min −1 [93].…”

Facile Synthesis of Hydrogel-Based Ion-Exchange Resins for Nitrite/Nitrate Removal and Studies of Adsorption Behavior

“…In the liquid–solid system, the diffusion rate of nitrate or nitrite was determined using the intraparticle diffusion model which was proposed by Weber and Morris [ 62 ] and McKay and Poots [ 63 ]. The linearized equation can be expressed as Equation (8), where k p is the intraparticle diffusion coefficient (mg/g min 0.5 ), and C is the intercept which is constant for the experiment [ 64 ]. The values of the intraparticle diffusion coefficient and r 2 can be found by plotting q t against t 0.5 and are shown in Table 1 and Table 2 .…”

Visible‐Light‐Enhanced Photocatalytic Activity of Totally Inorganic Halide‐Based Perovskite

“…where k d is the intraparticle diffusion rate constant (mg g −1 min −0.5 ). According to the model, when the plot of q t versus t 1/2 is given by overlapping lines, two or more steps govern the adsorption process . Figure C shows the intraparticle diffusion plot obtained from the adsorption tests performed.…”