Synthesis of ecological chitosan/PVP magnetic composite: Remediation of amoxicillin trihydrate from its aqueous solution, isotherm modelling, thermodynamic, and kinetic studies

Arsenic removal performance and mechanism from water on iron hydroxide nanopetalines

“…2 b, the adsorption–desorption isotherms of the adsorbent did not exhibit a plateau at high p/p 0 values. According to the IUPAC classification, its isotherms could be assigned to type IV isotherms with H3-type hysteresis loops, indicating the adsorption of N 2 by these pores, which were produced by aggregation of the platelet-like particles, was multilayered physical adsorption 38 , 40 . The adsorption isotherms of the adsorbent did not exhibit a plateau at high p/p 0 values.…”

“…Pseudo-first-order, pseudo-second-order and Elovich models were used to fit the adsorption kinetics data in order to investigate the characteristics of the adsorption process. The linear forms of these models can be described as follows 40 , 42 : where q e (mg/g) and q t (mg/g) are the adsorption amounts of arsenic at equilibrium and at time t , respectively, and k 1 (h −1 ) and k 2 (g/(mg∙h)) are the rate constants of the pseudo-first-order and pseudo-second-order models, respectively. α (mg/g/h) and β (g/mg/h) are the Elovich coefficients, which are the initial adsorption rate and the desorption constant related to the extent of surface coverage and the activation energy of chemisorption, respectively 35 , 43 .…”

“…The Langmuir, Freundlich and Temkin adsorption isotherm models, were applied to simulate the adsorption isotherm data. The linear expressions of these isotherm models could be represented in the following 40 , 42 : where C e (mg/L) is the arsenic concentration at equilibrium, q e (mg/g) and q max (mg/g) stand for the equilibrium and maximum adsorption capacities, respectively, K L (L/mg) is the Langmuir model constant, K F ((mg/g)·(mg/L) –1/ n ) and n are the adsorption constants of the Freundlich model. K L and K F roughly represent the adsorption affinity between arsenic and the adsorption sites.…”

“…3 a,b). For the simulation of the Temkin model, the values of bonding energy (b) ranged from 70.61 to 155.82 J/mol, suggesting that the arsenic removal process was both chemisorption and physisorption 40 , 45 .…”

Investigating the adsorption behavior of functional biochar-based porous composite for efficiently removing Cu(ii) in aqueous solution

“…The isotherm is one of the most important parameters to describe the type of interaction between an adsorbent and an adsorbate. 39 The Langmuir model is based on the hypothesis that the metal ions are covered by a monolayer at the adsorbent. 36 Moreover, the Freundlich isotherm presumes that the multilayer of the adsorption process occurs on a heterogeneous surface.…”