Use of Adsorbent Biochar from Pequi (Caryocar Brasiliense) Husks for the Removal of Commercial Formulation of Glyphosate from Aqueous Media

Abstract This study evaluated the capacity of adsorbent biochar derived from pequi husks to remove glyphosate (commercial formulation) in aqueous medium under three pH conditions (5.5, 7.0 and 8.0). This biochar presented a mean yield of 33.1% ± 2.66% and a high amount of surface particles of small dimensions endowing it with high surface area. The results showed that removal is proportional to pH increase in the range of 5.5 to 8.0. Adsorption assays performed at pH 7 and 8 fitted better to the Langmuir pseudo-first order kinetics model with fast adsorption in the first 15 to 30 minutes. The results for the acidic pH range fit none of the adopted models satisfactorily. The results obtained suggest that adsorbent can be used as an efficient and inexpensive alternative for the adsorption of glyphosate present in commercial formulations from aqueous matrices.

Adsorption of Cd[II] from aqueous solution by modified and chelated cellulose

The preparation of modified and chelated cellulose adsorbents and its biosorption behaviors of Cd[II] have been studied. Effect of different chemical modifications and its adsorbent properties including different alkalis saponification [NaOH, NH40H] and different acids [citric and oxalic acids] modification after saponification with NaOH were investigated. The infrared spectra showed that there are different functional groups in biosorbents which are able to react with metal ion in aqueous solution. In addition, influences of pH, contact time, and initial concentration of Cd [II] on sorption of Cd [II] were discussed. Different models are used to fit experimental data. Results showed that experimental data follows Langmuir and Freundlich models, and pseudo-second order model. The maximum adsorption capacities obtained from Langmuir model are 76.92 and 122.50 mg g-1 by using control [non modified] and modified biosorbents as an average, respectively. Equilibrium time was obtained at 105 mm, and was accelerated to reach 90 mm. by using the modified treatments. The optimum pH value was 6. Therefore, cellulose can be used as an effective biosorbent for removing Cd [II] from aqueous solution