Scavenging of copper(II) ions, phosphate(V) ions, and diuron from aqueous media by goethite modified with chitosan or poly(acrylic acid)

Abstract

Goethite was modified by chitosan (CS) or poly(acrylic acid) (PAA) to improve its adsorptive abilities toward components of agrochemicals, i.e., copper ions (Cu), phosphate ions (P), and diuron. The pristine goethite effectively bound Cu (7.68 mg/g, 63.71%) and P (6.31 mg/g, 50.46%) only in their mixed systems. In the one adsorbate solutions, the adsorption levels accounted for 3.82 mg/g (30.57%) for Cu, 3.22 mg/g (25.74%) for P, and 0.15 mg/g (12.15%) for diuron. Goethite modification with CS or PAA did not yield spectacular results in adsorption. The maximum increase in adsorbed amount was noted for Cu ions (8.28%) after PAA modification as well as for P (6.02%) and diuron (24.04%) after CS modification. Both goethite modifications contributed to clear reduction in desorption of pollutants (even by 20.26% for Cu after PAA coating), which was mainly dictated by electrostatic attractive forces and hydrogen bonds formation occurring between macromolecules and impurities. The only exception in this phenomenon was Cu desorption from CS-modified solid—the polymer made it higher (to 95.00%). The Cu adsorption on PAA-modified goethite enhanced solid aggregation and thus facilitated metal cation separation from aqueous media. Consequently, the goethite modification with PAA was considered more promising for environmental remediation.

Unravelling the kinetics, isotherms, thermodynamics, and mass transfer behaviours of Zeolite Socony Mobil - 5 in removing hydrogen sulphide resulting from a dark fermentative biohydrogen production process

“…The theory presupposes a consistent pore diffusivity and proposes that the adsorbate diffuses radially. 57 Eqn (12) is the linearised equation of IPD. q t (mg g −1 ) is the concentration of H 2 S adsorbed per mass of ZSM-5 at time ( t ).…”

Comparison of Structural, Water‐Retaining and Sorption Properties of Acrylamide‐Based Hydrogels Cross‐Linked by Physical and Chemical Methods

“…The experimental data of heavy metal sorption on other acryl-based hydrogels with clays were also commonly consistent with the Langmuir model, indicating good correlation between sorbed Cd(II) amounts and number of sorbent active sites as well as monolayer character of metal sorption. [2,2,42,44,69] The results of the study on contact time influence on sorbed Cd(II) amount on the hydrogels is depicted in Figure 7. As can be seen, sorption has a similar trend for all the samples: the fast increase of adsorbed amounts at first and reaching of the plateau later.…”