Removal of RR-23 dye from industrial textile wastewater by adsorption on cistus ladaniferus seeds and their biochar

The use of low-cost, easily obtained and eco-friendly adsorbents has been employed as an ideal alternative for the methods of removing dyes from wastewater. Cistus ladaniferus seeds (CLS) and their biochar (BCCLS) are the biomaterials used as a bio-adsorbent for removing of Reactive red 23 (RR-23). The bio-char of cistus seed is prepared by a thermo-chemical route known as pyrolysis under optimum conditions, temperature equal to 450 °C, heating rate 21 °C.min-1 and particle sizes of 0.3 to 0.6 mm after the BCCLS is grinded with a ceramic grinder until the particle size is between 0.1 and 0.2 mm. The kinetics adsorption of dye by CLS and BCCLS are correctly described by the pseudo-2nd-order model with a correlation factor (R2 = 0.997) and (R2 = 0.998) respectively. As for the modeling of the adsorption isotherm, among the four models tested, Lungmuir type II and type I is most appropriate with a correlation factor equal to 0.999 and 0.98 for the BCCLS and the CLS respectively. On the other hand, the ability to remove the dye by the BCCLS is advantageous and the elimination efficiency reaches a maximum value of 99.237% for the BCCLS and 82% for the CLS. Keywords: Biochar, Isotherm, Adsorption, Cistus Seed, pyrolysis, Technical analysis

Removal of Reactive Yellow 160 from Industrial Wastewater onto Modified Sand (Sand of Larache city beach. Morocco)

The aim of this research paper is to investigate the removal of Reactive Yellow 160 (RY160) from industrial wastewater onto Modified Sand (MS). The adsorbent was characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDXA). The effects of significant parameters such as adsorbent dose, pH, initial dye concentration, contact time, temperature were examined. It was revealed that the removal rate percentage was equal to 92.6%, the maximum adsorption capacity appeared at pH 1, and the optimal contact time for the removal of RY160 onto MS was 120min. Adsorption kinetics, isotherms and thermodynamic parameters were studied. The finding shows that the Langmuir isotherm and the Pseudo-second order kinetic model described well the adsorption process. The thermodynamic study disclosed that the adsorption of RY160 onto MS is exothermic and spontaneous with a physisorption nature. Keywords: Modified Sand, Reactive Yellow 160 (RY160), Adsorption, wastewater treatment, Industrial dyes

Removal of Reactive Yellow 135 from Wastewaterof Textile Industry onto Chitosan Extracted by Hydrothermo-Chemical Method.

The capabilities of chitosan for removing anionic dyes as reactive yellow 135 from wastewater of textile industry were examined. The chitosan was extracted from shrimp co-products "PandalusBorrealis" by the hydrothermo-chimical method in two steps. The bio-adsorbent obtained was characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDXA). Operational parameters studied were pH, contact time, adsorbate and adsorbent concentrations with a removal rate percentage of 98% and a maximum adsorption capacity of 69.244 mg/g at pH 1.9. Adsorption kinetics for the removal of reactive yellow 135 onto chitosan followed pseudo-second-order kinetics model. The examination of the isotherm data showed that the Freudlich isotherm model is the best fitting model. Keywords : Chitosan, Reactive Yellow 135 (RY135), Adsorption, Wastewater treatment, Industrial dyes, Textile industry

Modified Chitosan Immobilized on Modified Sand for Industrial Wastewater Treatment in Multicomponent Sorption: Shrimp Biowaste Processing

In this paper, modified chitosan immobilized on modified sand (MCs/MS) was synthesized and characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDXA). MCs/MS composite was used to remove Reactive Red 23 (RR23), Reactive Blue 19 (RB19) and Iron III (Fe3+) in three single-component and three binary, RR23+RB19, RR23+Fe3+ and RB19+Fe3+. Batch experiments were carried out for adsorption kinetics, isotherms and thermodynamics. Operational parameters studied were pH, contact time, temperature, adsorbate and adsorbent concentrations. Adsorption kinetics in single and binary systems of components followed pseudo- second-order kinetics model. The isotherm data in single and binary systems followed Freundlich isotherm model. Thermodynamic parameters have disclosed that the adsorption is exothermic and not spontaneous with a physical adsorption for both single and binary systems. The results showed that MCs/MS composite was an effective adsorbent to remove hazardous pollutants with a removal rate between 80% and 99.6%, the optimal contact time was between 120 and 180 min for all components in single and multicomponent system. Keywords : Modified chitosan immobilized on modified sand, Multicomponent system, Reactive Red 23, Reactive Blue 19, Iron III, Hydrothermo-Chemical method

Synthesis and characterization of arginine-doped heliotrope leaves with high clean-up capacity for crystal violet dye from aqueous media

Novel an arginine-modified Heliotrope leaf (Arg@HL) was used as adsorbent for the crystal violet (CV) dye adsorption in a batch process. The physicochemical and morphological composition of Arg@HL were characterized by field-emission-scanning-electron-microscopy (FE-SEM), Fourier transforms infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC). The experiments were carried out to investigate the factors that influence the dye uptake by the adsorbent, such as the contact time under agitation, adsorbent amount, initial dye concentration, temperature and pH of dye solution. The optimum conditions of adsorption were found on the batch scale as followed: CV concentration of 20 mg center dot L-1, an amount of 0.75 g center dot L-1 of the adsorbent, 90 min contact time, 6 pH and 25 degrees C temperature for Arg@HL. The results confirmed a second-order model explaining the dye crystal violet's adsorption's kinetics by Arg-Heliotrope leaves. The Langmuir model effectively defines the adsorption isotherms. The results revealed that the Arg@HL has the potential to be used as a low-cost adsorbent for the removal of CV dye from aqueous solutions

Photocatalytic oxidation of pollutants in gas-phase via Ag3PO4-based semiconductor photocatalysts: Recent progress, new trends, and future perspectives

Air pollution has become a significant challenge for both developing and developed nations. due to its close association with numerous fatal diseases such as cancer, respiratory, heart attack, and brain stroke. Over recent years, heterogeneous semiconductor photocatalysis has emerged as an effective approach to air remediation due to the ease of scale-up, ready application in the field, use of solar light and ready availability of a number of different effective photocatalysts. To date, most work in this area has been conducted using UV-absorbing photocatalysts, such as TiO2 and ZnO; However, recent studies have revealed Ag3PO4 as an attractive, visible-light-absorbing alternative, with a bandgap of 2.43 eV. In particular, this material has been shown to be an excellent photocatalyst for the removal of many types of pollutants in the gas phase. However, the widespread application of Ag3PO4 is restricted due to its tendency to undergo photoanodic corrosion and the poor reducing power of its photogenerated conductance band electrons, which are unable to reduce O2 to superoxide •O2−. These limitations are critically evaluated in this review. In addition, recent studies on the modification of Ag3PO4 via combination with the conventional heterojunctions or Z-scheme junctions, as well as the photocatalytic mechanistic pathways for enhanced gas-pollutants removal, are summarized and discussed. Finally, an overview is given on the future developments that are required in order to overcome these challenges and so stimulate further research into this promising field

La 1-canavanine: produit toxique des graines de soja et de luzerne. Identification par chromatographie liquide a haute performance. Complexations binaire et ternaire avec Cu(II), Ni(II) et Zn(II)

SIGLEINIST T 74832 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Development of a novel PANI@WO3 hybrid composite and its application as a promising adsorbent for Cr(VI) ions removal

In the current study, an in-situ oxidative polymerization method was used to synthesize polyaniline-coated tungsten trioxide biphasic composite (PANI@WO3). The as-developed composite material properties were elucidated using different characterization tools such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), N2 sorption-desorption isotherm, and X-ray photoelectron spectroscopy (XPS). The PANI@WO3 was further applied to remove hexavalent chromium (Cr(VI)) from aqueous solutions. The results demonstrated that the optimal removal efficacy was achieved at pH 2. Meanwhile, the pseudo-second-order kinetic and isotherm of the Langmuir model were fitted for Cr(VI) adsorption. Cr(VI) amount of 549.37 mg·g−1 was the maximum capacity of adsorption attained for PANI@WO3, which is significantly higher than that of existing adsorbents. From a thermodynamic point of view, the Cr(VI) adsorption process occurred spontaneously and endothermically. Importantly, PANI@WO3 still exhibited an excellent adsorption capability after five regeneration cycles, indicating the potential reusability of the PANI@WO3 composite. XPS analysis of PANI@WO3 surface after adsorption of Cr(VI) confirmed its adsorption and concomitant reduction into Cr(III) ions. The transfer of mass phenomenon, electrostatic attraction, and reduction reaction were the primary processes for Cr(VI) ions elimination. These findings revealed that the synthesized PANI@WO3 exhibited a high potential for wastewater treatment containing Cr(VI)

Synthesis of an arginine-functionalized polyaniline@FeOOH composite with high removal performance of hexavalent chromium ions from water: Adsorption behavior, regeneration and process capability studies

In this study, the synthesis of a novel arginine-functionalized polyaniline/FeOOH (Arg-PANI@FeOOH) composite for hazardous Hexavalent chromium ions (Cr(VI)) removal from wastewater was reported. The SEM, EDS, FTIR, XRD, and PZC measurements were used to characterize the as-developed Arg-PANI@FeOOH composite. Batch adsorption experiments were used to investigate the influence of pH, temperature, contact time, Arg-PANI@FeOOH amount, initial Cr(VI) concentration and coexisting ions on the efficiency of Cr(VI) removal. The Cr(VI) adsorption was much more advantageous at lower pH values, reflecting that the electrostatic interactions were the main driving forces that govern Cr(VI) binding mechanism on the Arg-PANI@FeOOH surface. The experimental data showed good fitness to the pseudo-second-order kinetics and Langmuir isotherm. The Cr(VI) species highest monolayer coverage capacity onto Arg-PANI@FeOOH was 682.30 mg g−1. The adsorption of Cr(VI) onto the Arg-PANI@FeOOH is spontaneous via an endothermic reaction. The competing anions were not affected the Cr(VI) adsorption, demonstrating that the Arg-PANI@FeOOH selectively adsorb Cr(VI) ions. The developed Arg-PANI@FeOOH material demonstrated good reusability up to five regeneration cycles. The process capability to predict the practical aptitude of Arg-PANI@FeOOH adsorbent to remove Cr(VI) from aqueous solutions was successfully applied. As a result, the adsorption of Cr(VI) onto Arg-PANI@FeOOH composite is a capable process for full-scale wastewater purification purposes. This paper provides relevant findings for a polyaniline-based adsorbent for the efficient removal of Cr(VI) from wastewater