An insight into the adsorption of diclofenac on different biochars: Mechanisms, surface chemistry, and thermodynamics

Abstract

Biochars were prepared from feedstocks pinewood and pig manure. Biochar microparticles obtained through grinding were evaluated for the removal of emerging contaminant diclofenac (DCF) and the underlying mechanism were thoroughly studied. Characterization of biochar was carried out using particle size analyzer, SEM, BET, FT-IR, XRD, XPS and zeta potential instrument. Pig manure biochar (BC-PM) exhibited excellent removal efficiency (99.6%) over pine wood biochar (BC-PW) at 500 µg L of DCF (environmentally significant concentration). Intraparticle diffusion was found to be the major process facilitated the adsorption. BC-PW followed pseudo first-order kinetics whereas BC-PM followed pseudo second-order kinetics. Pine wood biochar was largely affected by pH variations whereas for pig manure biochar, pH effects were minimal owing to its surface functional groups and DCF hydrophobicity. Thermodynamics, presence of co-existing ions, initial adsorbate concentration and particles size played substantial role in adsorption. Various isotherms models were also studied and results are presented.

Solution combustion synthesis of calcium aluminate nanocomposite using coffee husk extract as green fuel and its application in adsorptive amputation of anionic dyes

“…The negative values of ΔS 0 denote decreased randomness at the solid-liquid interface during the adsorption of CR on CHCA [68]. Multilayer adsorption on CHCA possibly reduces the randomness [72,73]. The isosteric heat of adsorption is another relevant thermodynamic parameter that efficiently describes the heat effects during the adsorption process and is a basic requirement for optimization of the adsorption process.…”

Mitigation of Diclofenac Pollution in Aqueous Media by Adsorption

“…Surface morphology of activated carbon from (a) Terminalia catappa fruit shell and (b) cocoa shell .…”

“…Suriyanon et al [54] utilized hexagonal mesoporous silicate modified with (3-aminopropyl)triethoxy or (3-mercaptopropyl)trimethoxy to impart specific functional groups (amine-or mercapto-) unto the mesoporous structure that would improve the affinity of the adsorbate to the adsorbent. Other [44] and (b) cocoa shell [48]. clays and minerals studied includes montmorillonite modified with octadecyltrimethyl ammonium or benzyldimethylhexadecyl ammonium [55], iron-pillared bentonite [56], molecularly imprinted polymer [57], commercial organoclay (Spectrogel Type C) ( Fig.…”

“…Pseudo-second order [85] GAC (functionalized with Fe) Freundlich Pseudo-second order [83] Moringa oleifera pod biosorbent Freundlich Pseudo-second order [80] Commercial AC Freundlich Intra-particle diffusion [80] Lignite activated coke Freundlich Pseudo-second order [79] Metal organic framework (UiO-66 type) Langmuir Pseudo-second order [71] Montmorillonite clay (modified by hexadecyltrimethyl ammonium) Langmuir - [52] AC from Terminalia catappa fruit shell Freundlich Intra-particle diffusion [44] AC from cocoa shell Liu General order [48] Hexagonal mesoporous silicate (modified by (3-mercaptopropyl)-trimethoxy)…”

Modified biochar from Moringa seed powder for the removal of diclofenac from aqueous solution

“…This interaction results in P-O-C linkages on the modified biochar to form a net negatively charged surface as (Wang et al 2017). The synthesized M SP B-HPO as a carbonaceous material is able to adsorb the pH modified Dfc via π-π interactions and these interactions are controlled by the changes in pKa of Dfc because changes in the pKa values can affect Dfc to take on cationic, neutral, or anionic character (Jiang et al 2015;Lonappan et al 2018). Furthermore, low-temperature synthesized biochars including M SP B are hydrophobic and adsorb pollutants effectively in an acidic phase (Fig.…”