Kinetic and isotherm insights of Diclofenac removal by sludge derived hydrochar

Abstract

Recently, hydrothermal carbonization emerges as the most viable option for the management of solid waste with high moisture content. Sludge derived hydrochar is used as an adsorbent for emerging contaminants or micro-pollutants in the domain of sustainability. Current study demonstrates the KOH activation of hydrochar produced from paper board mill sludge and evaluates its removal potential of a Non-steroidal anti-inflammatory drug, Diclofenac from aqueous solution. The activated hydrochars exhibited porous, spherical micro-structures with higher fraction of oxygenated functional groups paving way for the efficient adsorption of Diclofenac. The effect of initial Diclofenac concentration and contact time was ascertained using adsorption kinetics and isotherms. The adsorption kinetics exhibited second-order reaction for all adsorbents indicating higher coefficient of determination (R2 > 0.9). The Diclofenac adsorption on hydrochars followed Langmuir isotherm model with the post-activated hydrochar recording a highest adsorption capacity of 37.23 mg g−1 in 40 mg L−1 initial Diclofenac concentration at 15 h equilibrium time.

Chemical activation of Microcystis aeruginosa biomass: a promising approach for enhanced diclofenac sorption and water treatment

“…In this case, the native biomass of M. aeruginosa ACCMU‐118 exhibited a DCF binding site capacity of 12.67 μmol. However, the Temkin model performed poorly in fitting the experimental data, consistent with other studies 79 …”

“…However, the Temkin model performed poorly in fitting the experimental data, consistent with other studies. 79 Sorption and removal of DCF by pretreated biomass Previous studies have indicated limited accessibility of binding sites in algal biosorbents for metal ions. 45,[80][81][82] Chemical treatments have been proposed to enhance binding site accessibility.…”

Sorption of Mercury in Batch and Fixed-Bed Column System on Hydrochar Obtained from Apple Pomace

“…The PZC point determined by this method is 7.3, by which it can be concluded that neither positive nor negative charges dominate the surface. This result is similar to the result of 7.6 obtained by Oumabady et al for hydrochar obtained from paper board mill sludge [44].…”

Phosphoric acid surface modified Moringa oleifera leaves biochar for the sequestration of methyl orange from aqueous solution: Characterizations, isotherm, and kinetics analysis

“…Langmuir isotherm model assumes monolayer coverage of the homogenous energy distributed active sites containing surface (Islam et al, 2018). Instead of predicting monolayer coverage, the Freundlich isotherm model utilizes the concept of multilayer sorption (Oumabady et al, 2022) of foreign molecules, e.g., dyes, metals, etc., on the heterogeneous surfaces of the sorbents (Takkar et al, 2022). This study analyzed the MO molecules and biochar system using Langmuir and Freundlich models.…”