In this study, a low cost carbon adsorbent was prepared from date seeds. Their surface was modified with potassium hydroxide for use as an adsorbent for the removal of synthetic dye (methyl orange (MO)) from aqueous solutions. The effects of initial MO concentration, adsorbent dosage and temperature were studied. A two-cubed (23) factorial design was carried out on the experimental data, with two replications for the process optimization. The results showed that all three factors and their interactions up to the third order were significant for the removal efficiency of MO. Maximum equilibrium adsorption capacity was 66.26 mg/g at 318 K.

Elevated humidity levels in medical, food, and pharmaceutical products may reduce the products' shelf life, trigger bacterial growth, and even lead to complete spoilage. In this study, we report a humidity indicator that mechanically bends and rolls itself irreversibly upon exposure to high humidity conditions. The indicator is made of two food-grade polymer films with distinct ratios of a milk protein, casein, and a plasticizer, glycerol, that are physically attached to each other. Based on the thermogravimetric analysis and microstructural characterization, we hypothesize that the bending mechanism is a result of hygroscopic swelling and consequent counter diffusion of water and glycerol. Guided by this mechanism, we demonstrate that the rolling behavior, including response time and final curvature, can be tuned by the geometric dimensions of the indicator. As the proposed indicator is made of food-grade ingredients, it can be placed directly in contact with perishable products to report exposure to undesirable humidity inside the package, without the risk of contaminating the product or causing oral toxicity in case of accidental digestion, features that commercial inedible electronic and chemo-chromatic sensors cannot provide presently.