Cellulose was modified under mild conditions in order to increase its capability to trap pollutants. Nicotinoyl chloride hydrochloride (NCHC), with its pyridine ring able to adsorb cations, was grafted on the substrate. This grafting has been monitored by infrared spectroscopy and elemental analysis. We have studied the adsorption of Methylene Blue (MB) onto grafted and unmodified cellulose. It was observed that grafting increases three times the retention capacity of cellulose and the kinetics of adsorption is perfectly represented by a pseudo second order model. The adsorption is well described by a Langmuir-type isotherm showing a homogeneous adsorption phenomenon through the formation of a monolayer. Besides the reaction is spontaneous and exothermic, suggesting the possibility of recycling the substrate by desorbing the dye at elevated temperature.

During the present study, biopolymer lignin was extracted, in particular, from sugar beet pulp (molasses) from the Tadla region (224 km from Marrakech, Morocco). The lignin was characterized by infrared spectroscopy (FTIR) and thermogravimetric TG/DTA analysis and then used as a modifier to enhance the electroanalytical detection of heavy metal ion traces. The performance of the lignin/CPE sensor to detect lead (II) was studied by cyclic voltammetry (CV) and square-wave voltammetry in 0.3 mol L−1 NaCl. With optimized experimental parameters, the lignin/CPE sensor developed has a minimum detection limit of 2.252.10−11 M for Pb (II). The proposed working electrode has been successfully applied for the coanalysis of Pb (II) in tap water with good results.

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This study focused on the adsorption in aqueous solution of methylene blue (MB), a cationic dye used in the textile industry, by crushed Argan shells (used as raw materials) from the southern region of Morocco. These crushed Argan shells were first characterized by different technical analyses: elemental analysis, biochemical analysis, IR spectroscopy, thermogravimetric analysis, scanning electron microscopy, mercury porosimetry, and zetametry. The adsorption kinetics was then studied by varying the experimental parameters such as the dye concentration in solution. We note that at pH = 8 , there is an elimination up to 232.6 mg/g, during an equilibrium time of 180 min. The correlation coefficient showed that the pseudosecond-order kinetic equation best describes the adsorption kinetics for the tested material. The adsorption isotherms of MB by Argan shells are suitably described by the Langmuir model which provide the best theoretical correlation of the experimental data. The thermodynamics of MB adsorption on Argan shells indicates a spontaneous and endothermic process. It was concluded that an increase in temperature leads to a greater adsorption of MB by the studied biosorbent.