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The purpose of this paper is to focus on the removal of copper(II) ions from aqueous model salt solution by using chitosan-coated magnetite nanoparticles.

The chitosan-coated magnetite nanoparticles were characterized using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric differential thermal analysis. The adsorption of Cu(II) by using magnetite nanoparticles as an adsorbent was investigated under different adsorption conditions. The parameters studied were contact time, adsorbent dose and initial concentrations.

The sorption capacities of prepared samples were studied for the removal of Cu²⁺ ions from aqueous model solutions with varying experimental conditions of the initial metal concentration, contact time and dosage. It is found that the removal percent of Cu²⁺ ions increases with an increase in initial metal concentration, contact time and amount of dosage.

Based on the obtained results, this study recommends that chitosan-coated magnetite nanoparticles can also be applied for removal of some heavy metal ions and/or organic compounds in aqueous solution. It is recommended that this study be shared with the polymer-based nanomaterial researchers, especially material science.

The purpose of this study was to estimate on-farm maize storage losses and to empirically analyse the main determinants of maize storage losses in China.

Based on a nationwide survey of 1,196 households in 23 provinces (autonomous regions and municipalities) in China, the authors estimated on-farm maize storage losses and used a fractional logit model to analyse the main determinants of maize storage losses in China.

The results showed that, first, 1.78% of maize was lost during the storage stage in China and that storage loss experienced by smallholders varied across regions. Second, the empirical analysis showed that storage quantities have significant and negative effects on storage losses and that an economy of scale in household storage may exist; the percentage of maize stored for consumption and feed has significant and positive effects on storage losses, which may be related to market requirements and management activities. Third, compared to traditional facilities, silos and warehouses cause lower storage losses, while spraying chemicals and re-drying maize in the storage stage incur higher losses, possibly because to save costs, smallholders conduct loss-reduction activities only when they suffer serious losses, and when taking measures, farmers may sort grains, which also increases losses. Fourth, harvesting maize when it matures is significantly associated with lower storage losses.

To reduce storage losses, first, farmers' awareness of food saving and loss reduction must be increased. This could be achieved through agricultural training and education regarding food-saving practices. Second, the government could provide subsidies or low-interest credits to encourage farmers to use advanced facilities and promote land transfers to realize economies of scale. Finally, the government should accelerate the construction of smart agriculture systems and the timely monitoring of crop growth to suggest farmers to harvest at the appropriate time.

Reducing post-harvest loss (PHL) has become an important means of increasing the food supply and reducing resources use in China. This study provides a complete introduction to household maize storage losses and can therefore help characterize the current state of PHL in China, which is of vital importance to food security and food policy.