Natural macromolecule adsorbing materials are alternatives for remediation of heavy metals’ polluted waters. In this study, sodium alginate composite gel (SACL) was synthesized from sodium alginate (SA), polyethylene glycol oxide (PEO), and nanomaterials to remove wastewater Cu (II) and Cd (II). The adsorption efficiency of SACL was analysed in relation to the contact time, initial concentrations of metal ions, temperature, adsorbent dosage, and solution pH. Three models, i.e., kinetic model, isothermal adsorption model, and thermodynamic model, were used to fit the experimental data. Our results showed that the highest removal rates of Cu (II) and Cd (II) from wastewater were 96.8% and 78%, respectively, under the condition of the best liquid-solid ratio of 12.5 ml·g−1, and the contact time of 180 min (25°C). Overall, the SACL adsorption of Cu (II) and Cd (II) was spontaneous. The adsorption kinetics and the isothermal adsorption were fitted well with the pseudo-second-order kinetic equation and Langmuir equation, respectively. Combined with SEM-EDS and FTIR analysis, results suggested that SACL adsorbs wastewater Cu (II) and Cd (II) mainly through chemical reaction on its surface area. Altogether, this work concludes on SACL as an efficient and ecofriendly adsorbent for wastewater Cu (II) and Cd (II).

Mesoporous ceramic functional nanomaterials (MCFN) is a self-assembled environmental adsorbent with a monolayer molecular which is widely used in the treatment of industrial wastewater and contaminated soil. This work aimed to study the relationship between the adsorption behaviour of Cd(II) by MCFN and contact time, initial concentration, MCFN dosage, pH, oscillation rate and temperature through a batch adsorption method. The adsorption kinetic and isotherm behaviours were well described by the pseudo-second-order and Langmuir models. The batch characterization technique revealed that MCFN had several oxygen-containing functional groups. Using Langmuir model, the maximum adsorption capacity of MCFN for Cd(II) was 97.09 mg g −1 at pH 6, 25°C, dosage of 0.2 g and contact time of 180 min. Thermodynamic study indicated that the present adsorption process was feasible, spontaneous and exothermic at the temperature range of 25–55°C. The results of this study provide an important enlightenment for Cd removal or preconcentration of porous ceramic nanomaterial adsorbents for environmental applications.

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The present study, via a 180-days field trial, investigated the potential of chelate tetrasodium glutamate diacetate (GLDA) for the remediation of cadmium (Cd)-contaminated farmlands by French marigold. To do so, five GLDA treatments (e.g., 0, 292.5, 585, 1170, and 2340 kg hm− 2) were practiced. For each treatment, the total GLDA was divided into two applications with 15 day intervals (0.25, 0.47, and 0.61 mg·kg− 1) under French marigold plantation. Compared with the control, our results showed that GLDA application significantly increased the biomass of aerial parts of French marigold by 21.9% (p < 0.05). Likewise, Cd content in aboveground and underground parts of French marigold increased by 94.7% and 60.5%, respectively, compared with the control (p < 0.05). GLDA application caused significant increases in Cd accumulations in cell soluble fraction and cell wall by 290% and 123%, respectively (p < 0.05); Soil pH and DTPA-Cd content increased with the increase of total application of GLDA. Co-application of GLDA (2340 kg hm− 2) and French marigold reduced the total soil Cd content by 12.87% compared with the soil background. Altogether, our findings conclude on the efficacy of GLDA application for the remediation of Cd contaminated farmlands under French marigold cultivation.