Synthesis of novel biocomposite powder for simultaneous removal of hazardous ciprofloxacin and methylene blue: Central composite design, kinetic and isotherm studies using Brouers-Sotolongo family models

Over the past decades, extensive efforts have been made to use biomass-based-materials for wastewater-treatment. The first purpose of this study was to develop and characterize regenerated-reed/reed-charcoal (RR-ChR), an enhanced biosorbent from Tunisian-reed (Phragmites-australis). The second aim was to assess and optimize the RR-ChR use for the removal of binary ciprofloxacin antibiotic (CIP) and methylene blue dye (MB), using Central Composite Design under Response Surface methodology. The third purpose was to explain the mechanisms involved in the biosorption-process. The study revealed that the highest removal-percentages (76.66 % for the CIP and 100 % for the MB) were obtained under optimum conditions: 1.55 g/L of adsorbent, 35 mg/L of CIP, 75 mg/L of MB, a pH of 10.42 and 115.28 min contact time. It showed that the CIP biosorption mechanism was described by Brouers–Sotolongo-fractal model, with regression-coefficient (R2) of 0.9994 and a Person’s Chi-square (X2) of 0.01. The Hill kinetic model better described the MB biosorption (R2 = 1 and X2 = 1.0E-4). The isotherm studies showed that the adsorbent surface was heterogeneous and the best nonlinear-fit was obtained with the Jovanovich (R2 = 0.9711), and Brouers–Sotolongo (R2 = 0.9723) models, for the CIP and MB adsorption, respectively. Finally, the RR-ChR lignocellulosic-biocomposite-powder could be adopted as efficient and cost-effective adsorbent

Bacteria in Soil: Promising Bioremediation Agents in Arid and Semi-Arid Environments for Cereal Growth Enhancement

International audienceIn arid regions, starchy agricultural products such as wheat and rice provide essential carbohydrates, minerals, fibers and vitamins. However, drought, desiccation, high salinity, potentially toxic metals and hydrocarbon accumulation are among the most notable stresses affecting soil quality and cereal production in arid environments. Certain soil bacteria, referred to as Plant Growth-Promoting Rhizobacteria (PGPR), colonize the plant root environment, providing beneficial advantages for both soil and plants. Beyond their ability to improve plant growth under non-stressed conditions, PGPR can establish symbiotic and non-symbiotic interactions with plants growing under stress conditions, participating in soil bioremediation, stress alleviation and plant growth restoration. Moreover, the PGPR ability to fix nitrogen, to solubilize insoluble forms of nutrients and to produce other metabolites such as siderophores, phytohormones, antibiotics and hydrolytic enzymes makes them ecofriendly alternatives to the excessive use of unsuitable and cost-effective chemicals in agriculture. The most remarkable PGPR belong to the genera Arthrobacter, Azospirillum, Azotobacter, Bacillus, Enterobacter, Klebsiella, Pseudomonas, etc. Therefore, high cereal production in arid environments can be ensured using PGPR. Herein, the potential role of such bacteria in promoting wheat and rice production under both normal and derelict soils is reviewed and highlighted. © 2022 by the authors

Ba2+ removal from aquatic medium via TiY2O5@g-C3N4 nanocomposites

International audienceThis research intends to produce TiY2O5@g-C3N4 nanocomposite that can be utilized to eliminate Ba+2 from aqueous solutions. The nanocomposite was studied with XRD, BET, EDX, and TEM investigation. The TiY2O5@g-C3N4 nanocomposite sorption effectiveness was studied by contact time, adsorbent dose, beginning pH, and initial barium ions concentration in batch kinetic and equilibrium tests. The barium ions adsorption was conducted using 10 mg of adsorbent, 60 mg. L−1 initial Ba+2 concentration at pH = 7 and equilibrium was reached in within 54.5 min. The Langmuir isotherm offered the highest correlation for Ba+2 adsorption to TiY2O5@g-C3N4 and demonstrated favorable adsorption; a maximum adsorption capacity of 295.52 mg. g−1 was achieved. The experimental data was utilized to study adsorption mechanisms and potential rate-controlling stages for mass transfer and kinetic models. External mass transfer and intra-particle diffusion influenced barium adsorption, and adsorption's kinetics followed a pseudo-second-order model with R2 = 0.9996, t1/2 = 38.8 min and h0 = 1.51 mg.g−1.min−1. The results indicate that Ba+2 are chemisorbed on TiY2O5@g-C3N4 nanocomposite. The results indicate that the nanocomposite has high aptitude and reusability for an effective metal ions adsorption

Parametrical Study for the Effective Removal of Mordant Black 11 from Synthetic Solutions: Moringa oleifera Seeds’ Extracts Versus Alum

International audiencePrior studies have examined the ability of Moringa oleifera (MO) seed extract, among other natural coagulants, to remove several types of dyes. MO has been proven to have a high capacity to remove some anionic dyes. The aim of the present study is to explore the possible use of aqueous and saline extracts of MO as biocoagulants for the removal of Mordant Black (MB11) from aqueous solution. Their performances were compared to that of aluminum sulfate (alum). To do so, various operating parameters were investigated such as coagulant dose (100–600 mg/L), pH (3–11), initial dye concentration (100–350 mg/L), sodium chloride concentration (0.2–2 M), and sedimentation time (15–90 min). The maximum percentages of MB11 removal were found to be 98.65%, 80.12%, and 95.02% for alum, aqueous extract of MO (MOPW), and saline extract of MO (MOPS), respectively, at around pH 6.5 and for coagulant doses of 400 mg/L (alum) and 500 mg/L (MOPW and MOPS). The coagulation-flocculation mechanism of biocoagulants was hypothesized to be adsorption and charge neutralization. The two biocoagulants (MOPW and MOPS) showed an interesting versatility towards pH counter to alum which was very sensitive to this parameter. pH variations were measured for the three coagulants and proven to be negligible for the biocoagulants. Faster sedimentation time was recorded when MOPW and MOPS were used, suggesting the existence of larger quickly settleable flocs. Considering their high coagulative capacity, rapid and cost-effective preparation, and eco-friendly character, MO extracts can be considered as powerful alternatives to aluminum sulfate in the remediation of MB11 from wastewaters. © 2022 by the authors

Revolutionizing dye removal: g-C3N4-Modified ZnO nanocomposite for exceptional adsorption of basic fuchsin dye

International audienceOrganic dye pollution poses a critical environmental challenge, necessitating sustainable solutions for effective removal. This study presents a g-C3N4-modified ZnO nanosorbent to remove Basic Fuchsin dye from aqueous solutions efficiently. Synthesis and comprehensive characterization (SEM, BET, XPS, FTIR, XRD) elucidated the nanosorbent's properties and adsorption performance and mechanisms. Experimental results demonstrate optimal performance under alkaline conditions, with significant adsorption capacity (up to 478.14 mg/g at 300 ppm dye concentration). Adsorption behavior is well-described by the Freundlich isotherm and pseudo-firstorder kinetic models. The nanosorbent demonstrates reusability and cost-effectiveness and exploits hydrogen bonding and 7C-7C interactions for adsorption. This work highlights the potential of g-C3N4@ZnO as a promising solution for mitigating dye pollution and promoting sustainable water treatment technologies