Improvement of humic acid (HA) removal using a new inorganic-organic composite coagulant: α-costic acid as a modifier of polyaluminum chloride properties.

In this work, α-costic acid (αCA), a plant sesquiterpenoid from Dittrichia viscosa, was grafted into polyaluminum chloride (PAC), forming a new eco-sustainable composite coagulant PAC-αCA with improved functionality. The α-costic acid fraction grafted into the PAC and the distribution of aluminum forms in the composite coagulant were evaluated for their effectiveness in removing bentonite and humic acid from synthetic water. The interaction mechanism between PAC and α-CA was examined by the Al-Ferron time spectrophotometric method, density functional theory (DFT), and FTIR analysis. By monitoring the aluminum speciation in the composite coagulant PAC-αCA, it was discovered that the introduction of α-CA impacted the distribution of various aluminum forms, including mononuclear Ala, highly polymeric Alb, colloidal, and medium polymeric Alc. The theoretical analysis identified the Alb species as particularly sensitive to reacting with α-CA. Furthermore, coagulation performance tests demonstrated that increasing the percentage of α-CA and promoting the prevalence of Alb and Alc species over Ala species in PAC-αCA led to improved removal of turbidity and UV254. This study provides an attractive and practical option for water treatment plants to remove colloidal suspensions in raw water effectively.

New insights on manganese dioxide nanoparticles loaded on cellulose-based biochar of cassava peel for the adsorption of three cationic dyes from wastewater.

Herein, a cost-effective nanomaterial with excellent adsorption capacity, simply prepared, using manganese dioxide (MnO2) nanoparticles (NP) loaded on cellulose-based biochar of an agricultural waste, which is cassava peel carbon (CPC) and denoted as MnO2-NP-CPC. MnO2-NP-CPC is an environmental-friendly, and efficient adsorbent analyzed using different technics such as x-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and energy dispersive x-ray spectroscopy (EDX). MnO2-NP-CPC was used to remove three different toxic dyes; methylene blue (MB), malachite green (MG), and rhodamine b (RB) from a single (MB), (MG), (RB), binary (MB + MG), (MG + RB), (MB + RB) and ternary (MB + MG + RB) wastewater systems, the impact of pH, adsorbent dose (2-8), initial dye concentrations (10-30 mg/L), temperature (15-35 °C) were fully studied. Furthermore, all the sorption experiments were done including adsorption isotherms, kinetics, and thermodynamics to explore all the mechanisms involved in the sorption of the three ionic dyes in single, binary, and ternary systems. The equilibrium experiments data fitted well the monolayer Langmuir isotherm for the single dye system with correlation coefficients close to 1 (0.98 for MB, 0.99 for MG, and 0.86 for RB), while the extended Langmuir and extended Freundlich isotherms were investigated to study the interaction of the three dyes in their binary systems, the obtained results indicate clearly that the sorption fellows the extended Langmuir model. Besides, the kinetic study showed the applicability of the pseudo-second model for the three dyes. Finally, the thermodynamic adsorption was controlled by physisorption, endothermic, and spontaneous in nature.

A novel biochar from Manihot esculenta Crantz waste: application for the removal of Malachite Green from wastewater and optimization of the adsorption process.

The adsorptive removal of Malachite Green (MG) by a novel biochar namely Cassava Rind Carbon (CRC) was studied in a batch system. Moreover, Box-Behnken Response Surface Methodology was used to optimize operating conditions of the adsorption process. Characterization was done by Thermo Gravimetric Analysis (TGA), Attenuated Total Reflectance Fourier Transform Infra-Red Spectroscopy (ATR/FTIR), Brunauer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and pH zero charge point (pHZCP). The pseudo-second-order model and Langmuir model provided the best fit for kinetic and isotherm, respectively. The maximum capacity of dye adsorbed was 932.98 mg/g at 25 °C. The influence of temperature, the mass of adsorbent and the concentration of dye was studied. The optimal amount of adsorbed MG was 1,363.58 mg/g corresponding to 50 °C, 5 mg of CRC and 150 mg/L of dye. According to the high performance exhibited by CRC in this study, Manihot esculenta Crantz waste can be used as a better and low-cost biomass for wastewater decolourization.

In vitro genotoxicity of Settat town landfill leachate, Morocco.

With the increasing use of landfill sites, leachates produced by uncontrolled waste disposal have became a serious threat for the aquatic environment. The aim of this study was to evaluate the genotoxicity of leachate and of well water sampled close to the town of Settat in Morocco using the micronucleus test and proliferation kinetics of human peripheral blood lymphocytes in vitro. We also analysed a number of physical and chemical parameters, including pH, % O2, chemical oxygen demand (COD), HCO3(-), Ca2+, Mg2+, Cl(-), and conductivity. The analysis showed much higher levels of nearly all parameters than the Moroccan standard. Increased micronucleus frequencies were also found for both leachate and well water. Preliminary results indicate that both types of water are genotoxic and pose environmental and human health risk.