Comparative analysis of removal of crude oil and some refined petroleum products from the environment using rice husk: Adsorption isotherm and kinetic studies

Abstract

Rice husk a low cost agricultural waste was assessed for its efficiency as an oil spill sorbent by comparing its oil (crude oil, diesel and kerosene) uptake with that of a standard conventional synthetic sorbent mat used in oil spill clean-up. The sorption process of crude oil, diesel and kerosene onto rice husk and the standard was studied using Langmuir, Freundlich, Elovich, Temkin and Dubinin-Radushkevich adsorption models while the sorption kinetics was studied using Lagergren pseudo-firstorder, pseudo-second-order, intraparticle diffusion and liquid film diffusion models. Suitable environmental applicability of both sorbents was also studied. The result of the study shows that rice husk sorbed3.30± 0.23g of crude oil, 2.50± 0.81 g of diesel and 1.95± 0.72g of kerosene per unit mass while the standard sorbed11.50± 0.54g of crude oil, 10.34± 0.77g of diesel and 8.20± 0.93g of kerosene per unit mass. About 2.46± 0.17g of sorbed crude oil, 1.60± 0.64g of sorbed diesel and 1.57± 0.11g of sorbedkerosene were recovered from a unit mass of rice husk, while, 9.67± 0.36g of sorbed crude oil, 8.40± 0.95g of sorbed diesel and 6.50± 0.49g of sorbed kerosene were recovered from a unit mass of synthetic sorbent mat. The amount of the sorbed oils retained by a unit mass of rice husk is about 0.84± 0.22g of crude oil (25 % of sorbed crude oil), 0.90± 0.97g of diesel (36 % of sorbed diesel), and 0.38± 0.90g of kerosene (20 % of sorbed kerosene), while, 1.83± 0.33g of crude oil (15 % of sorbed crude oil), 1.94± 0.97g of diesel (19 % of sorbed diesel) and 1.70± 0.89g of kerosene (20 % of sorbed kerosene) were retained by a unit mass of synthetic sorbent mat. The result of the study indicates that the standard is a better sorbent for oil removal than rice husk. Rice husk has the ability to retain sorbed oil which makes it a good sorbent when oil recovery is not required, but disposal. The sorption process for both sorbents follows the Langmuir isotherm. Intraparticle diffusion model and liquid film diffusion model were parts of the rate determining steps of the sorption process of the oils onto rice husk and the standard.

Oil Adsorption Kinetics of Calcium Stearate-Coated Kapok Fibers

“…Linear plotting of ln( 1 − F ) vs. t , where F is the fractional attainment of equilibrium ( F = q t /q e ), generates the liquid film diffusion rate constant k fd . A zero intercept suggests that liquid film diffusion would be rate-limiting [ 44 , 45 ].…”

Removal of Cadmium, Copper, and Lead From Water Using Bio-Sorbent From Treated Olive Mill Solid Residue

“…where q (adsorption capacity) is the amount of solute adsorbed per unit weight of sorbent at equilibrium measured in mg/g, C f is the adsorbate equilibrium concentration in solution measured in mg/L, q max is the maximum adsorption capacity measured in mg/g, and b is Langmuir adsorption constant (L/mg). 65 - 67 …”

“…A plot of ( C f / q ) against C f produces a linear graph with slope = (1/ q max ), and intercept = (1/ bq max ). 66 …”

“…where q (adsorption capacity) is the amount of solute adsorbed per unit weight of sorbent at equilibrium measured in mg/g, C f is the adsorbate equilibrium concentration in solution measured in mg/L, q max is the maximum adsorption capacity measured in mg/g, and b is Langmuir adsorption constant (L/mg). [65][66][67] The term q max is assumed to represent a fixed number of surface sites in the sorbent, and it should be constant and temperature-independent. It is determined merely by the nature of the sorbent.…”

“…A plot of (C f /q) against C f produces a linear graph with slope = (1/q max ), and intercept = (1/bq max ). 66 In this work; the equilibrium of the bio-sorption process was described by fitting the experimental data for single metal systems (Cd 2+ , Cu 2+ , and Pb 2+ ) with the Langmuir isotherm model. The investigation of each single metal ion system was performed by varying the initial metal ion concentration in the range of 20 to 200 mg/L, and the batch experiments were carried out under the optimum conditions.…”