Sodium alginate (SA), polyvinyl oxide (PEO), and ceramic nanomaterials were used to prepare alginate composite gel. The present study examined the removal rate and adsorption capacity of alginate composite gel for removal of wastewater As(III), Pb(II), and Zn(II). Batch experiments were conducted to study the influence of experimental parameters such as pH and temperature, as well as the mechanism of As(III), Pb(II), and Zn(II) adsorption with the new adsorbent. The results showed the high efficiency of sodium alginate composite gel for removal of wastewater As(III), Pb(II), and Zn(II). Under the condition of the best liquid-solid ratio and the contact time, the removal rates of As(III), Pb(II), and Zn(II) were 67.42%, 95.31%, and 93.96%, respectively. The pseudo-second-order kinetic equation was superior to fit the adsorption kinetics process. The isothermal adsorption models of As(III) and Pb(II) fitted well with the Freundlich model, and Zn(II) fitted well with the Langmuir model. The results of SEM, EDS, XPS, and FTIR analyses revealed that the adsorption process occurred mainly via chemisorption. The results of the present study suggest that new adsorbents can be effectively utilized for As(III), Pb(II), and Zn(II) removal from water.

The present field trial investigated the impacts of combined organic-inorganic fertilization (COIF) on crop quality, soil nutrients, and ecological risks (e.g., soil Cd) using the entire growth period of wheat. To do so, we set up seven different treatments in this study: control (CK); chemical nitrogen (N) fertilizer (CF); optimized fertilization (OF); organic fertilizer replacing 25% (T1) and 50% (T2) of chemical fertilizer; and organic N replacing 25% (M1) and 50% (M2) of chemical N fertilizer. Overall, our results suggested that COIF caused a significant increase in the yield of wheat. Compared with the CK, the highest wheat yield happened in M1 treatment (18.27%), although significant increases also occurred in T1 (13%), T2 (6.40%), and M2 (9.63%) treatments (P < 0.05). Besides, COIF increased the grain protein content by 31.9%. In terms of the soil properties, COIF could alleviate soil acidification while improving the cation exchange capacity (CEC). In addition, COIF treatments significantly increased the contents of total phosphorus, total potassium, available phosphorus, and available potassium, by 6.35–16.9%, 3.17–10.9%, 5.53–28.7%, and 2.6–12% (P < 0.05), respectively. Altogether, the results of the present work suggested that the replacement ratios of CF with 25%~50% cow manure are the most effective practices to improve the wheat yield, soil fertility, and the ecological sustainability of the study soils.

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.