In this study, spent mushroom compost was investigated as a biosorbent for the removal of textile dyes from aqueous solution. Batch adsorption method was implemented for the study and analysis of the pH function, biosorbent amount, and contact time of the biosorption process. Biosorption kinetics followed the pseudosecond-order kinetic model for Acid Red 111 (AR111) and Basic Red 18 (BR18), whilst biosorption of Levafix Braun E-RN (LB) was well described by pseudo-first-order and intra-particle diffusion models. The biosorption process was found to be spontaneous and exothermic. The biosorption data conformed best with the Langmuir model. The maximum adsorption capacities were found as 140.9, 400.0, and 169.5 mg g À 1 for AR111, BR 18 and LB, respectively. The results showed that spent mushroom compost can be utilized as low-cost biosorbent in treating colored dye effluents.

A silver nanoparticle decorated poly(thiophene) modified glassy carbon electrode (GCE) was prepared for determination of caffeic acid. The Ag/PTh/GCE surface was characterized by scanning electron microscopy (SEM) and energy‐dispersive X‐ray (EDX) spectroscopy. The modified electrode has shown higher electrocatalytic activity towards the oxidation of caffeic acid. The peak current of was found linear in the concentration range from 1.00×10−8 to 4.83×10−6 M with a detection limit of 5.3×10−9 M (S/N=3). The modified electrode was used for determination of CA concentration in red wine samples. The thermodynamic constants, entropy change (ΔS), enthalpy change (ΔH) and Gibbs free energy change (ΔG) were calculated as −166.34 J/(mol K), −154.24 kJ/mol and −104.75 kJ/mol at 25 °C, respectively.

In the present study, Oreganum onites L. stalks in natural and chemically modified with HNO 3 and H 3 PO 4 used as adsorbent for removal of both acidic and basic dyes from waters. The adsorption was studied as a function of pH and contact time by batch method. All tested biosorbents were characterized by FT-IR, scanning electron microscopy, and measuring the pH dependence of the zeta potential. The adsorption isotherms were fitted to Langmuir isotherm. The maximum adsorption capacity of dyes was 280.73 mg g À1 for Basic Red 18, 147.06 mg g À1 for methylene blue and 112.36 for Acid Red 111, which is comparable to that of other lignocellulosic materials. The modification process was considerably increased the biosorption capacity of lignocellulosic material, resulting in a 56-63% increase in the biosorption capacity of basic dyes and a 125% increase in the biosorption capacity of acidic dye. The present study illustrated that the most effective factors in the adsorption of basic dye were surface charge and acidic groups on lignocellulosic biosorbents, while non-electrostatic forces as well as electrostatic forces were also effective in the adsorption of acidic dye. In conclusion, Oreganum stalks can be considered as a very prospective adsorbent for the removal of tested basic and acidic dyes.

The pine cone and oak cups pulp were used as low-cost adsorbents for the removal of basic (Basic Red 18) and acidic (Acid Red 111) dyes and Cr (VI) from aqueous solutions. The adsorbents were modified by HNO3to improve their biosorption capacity. The adsorbents were characterized using scanning electron microscopy and FTIR spectroscopy. The zeta potential was determined as a function of the pH, in order to explain the effect of pH on electrostatic adsorption ability of biosorbent. Modification of adsorbents with nitric acid led to an increase in accessibility of some functional groups on the surface or a decrease in negativity of surface charge. The modification of pine cone increased its adsorption capacity for the basic dye, whereas the modification of oak cups pulp decreased the adsorption ability for basic dye to some extent. The adsorption isotherms fitted the Langmuir model. The adsorption capacities were found to be 142.85, 158.73, and 156.20 mg g-1 for modified and raw pine cone and oak cups pulp, respectively. The acidic dye and Cr (VI) adsorptions were much lower compared to basic dye on all tested adsorbents. The results indicated that the forest wastes (pine cone and oak cups pulp) were an attractive candidate for basic dyes from aqueous solution.

In the present study, the vine stem and modified vine stem were used as low cost adsorbents for the removal of acidic and basic dyes from aqueous solutions. A comparative study was also carried out with activated carbon obtained from vine stem and then the adsorption capacities of all adsorbents were evaluated by batch adsorption process. The effects of various adsorption parameters (initial pH, particle size, and contact time) were investigated. The modification of the vine stem with nitric acid increased its adsorption capacity for the basic dye. Both, vine stem and modified vine stem exhibited higher adsorption capacities than activated carbon. The adsorption capacities were found to be 322.58, 250, and 200 mg g À1 for modified, natural vine stem, and activated carbon, respectively. In the case of acidic dye, the pH strongly affected the adsorption capacity and the maximum dye uptake was observed at pH 2 for all adsorbents. The acidic dye adsorption was lower compared to basic dye on both biosorbents and activated carbon tested. The maximum acidic dye adsorption values (58.82 and 59.88 mg g À1 ) were obtained with the vine stem and activated carbon, respectively. In the case of lignocellulosic adsorbents, both surface charge and surface groups had main effect on the adsorption of basic dye, while adsorption mechanism in activated carbon was mainly through the physical adsorption. The results of comparative adsorption capacity of adsorbents indicated that vine stem or modified vine stem can be used as a low cost alternative to activated carbon in aqueous solution for basic dye removal.

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Zinc oxide nanoparticles doped graphene oxide modified glassy carbon electrodes (Zn‐GO/GCE) were fabricated for easy, cheap and practical detection of atenolol (ATE). The morphological and chemical characterizations of modified electrodes were carried out with scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS) and X‐Ray photoelectron spectroscopy (XPS). The amounts of the electrode modifiers and the differential pulse voltammetric parameters were optimized due to exhibited the best analytical response towards the determination of ATE. As a result, the calibration curves of ATE were obtained at Zn‐GO/GCE using DPV technique with two different linear parts: 7.8 ‐ 84 μmol L−1 and 167 μmol L−1 ‐ 639 μmol L−1. The detection limit (LOD) was also calculated as 2.50 μmol L−1. The fabricated electrode in this study is selective for ATE in the presence of some electroactive molecules. The practical, easy and cheap modified electrode was applied for the detection of ATE in atenolol medicine tablets with good recovery.

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