Polymer Waste Recycling of Injection Molding Purges with Softening for Cutting with Fresnel Solar Collector-A Real Problem Linked to Sustainability and the Circular Economy

A plastic injection waste known as "purge" cannot be reintegrated into the recycling chain due to its shape, size, and composition. Grinding these cannot be carried out with traditional mills due to significant variations in size and shape. This work proposes a process and the design of a device that operates with solar energy to cut the purges without exceeding the degradation temperature. The size reduction allows reprocessing, revalorization, and handling. The purges are mixtures of processed polymers, so their characterization information is unavailable. Some characterizations were conducted before the design of the process and after the cut of the purges. Some of the most representative purges in a recycling company were evaluated. The flame test determines that all material mixtures retain thermoplasticity. The hardness (Shore D) presented changes in four of the purges being assessed, with results in a range of 59-71 before softening and 60-68 after softening. Young's modulus was analyzed by the impulse excitation technique (IET), which was 2.38-3.95 GPa before softening and 1.7-4.28 after softening. The feasibility of cutting purges at their softening temperature was evaluated. This was achieved in all the purges evaluated at 250-280 °C. FTIR allowed for corroboration of no significant change in the purges after softening. The five types of purges evaluated were polypropylene-ABS, polycarbonate-ABS-polypropylene, yellow nylon 66, acetal, and black nylon 66 with fillers, and all were easily cut at their softening temperature, allowing their manipulation in subsequent process steps.

Antioxidants in Traditional Mexican Medicine and Their Applications as Antitumor Treatments

Traditional medicine in Latin America and mainly in Mexico represents an essential alternative for treating different diseases. The use of plants as medicine is the product of a rich cultural tradition of the indigenous peoples, in which a great variety of species are used for the treatment of gastrointestinal, respiratory, and mental diseases and some other sicknesses; the therapeutic efficacy that they possess is due to the properties that derive from the active ingredients of plants principally antioxidants, such as phenolic compounds, flavonoids, terpenes, and tannins. An antioxidant is a substance that, at low concentrations, delays or prevents substrate oxidation through the exchange of electrons. Different methods are used to determine the antioxidant activity and the most commonly used are described in the review. Cancer is a disease in which some cells multiply uncontrollably and spread to other parts of the body, a process known as metastasis. These cells can lead to the formation of tumors, which are lumps of tissue that can be cancerous (malignant) or noncancerous (benign). Generally, the treatment of this disease consists of surgery, radiotherapy, or chemotherapy, which have side effects that decrease the quality of life of patients, so new treatments, focusing on natural resources such as plants, can be developed. This review aims to gather scientific evidence on the antioxidant compounds present in plants used in traditional Mexican medicine, specifically as antitumor treatment in the most common cancer types worldwide (e.g., breast, liver, and colorectal cancer).

Lead Adsorption in Manganese Oxides as Powders and Coatings Supported on Silica Gel Beads and Tin Inverse Opal-Like Structures

Background:

Pollution in water is of concern because of its negative influence on human health and impact on ecosystems. Three-dimensional (3D) structures in the form of inverse opals and opals-like structures were constructed on a scale of millimeters for their use in the adsorption of heavy metals adsorption on manganese oxide-covered surfaces.

Objective:

Manganese oxides both, as commercial powders and as synthesized coatings by the chemical bath method, have a high capacity of lead ions adsorption. The inverse opals and opals-like structures increase the contact area and regulate the flux.

Methods:

The chemical bath method was used to coating surfaces of inverse opals and opals-like structures. The size of structures was proposed in millimeters to guarantee an easier flow of water.

Results:

The manganese oxide deposits were predominantly constituted by an amorphous phase. The present crystalline forms were identified as γ − MnO2, ε − MnO2, Birnessite, and pyrolusite. The best adsorption was obtained with Mn(II, III) and Mn(II), with 91.4% and 80.6%, respectively.

Conclusion:

Mn(II, III) and Mn(II) had approximately three times better performance than oxides of Mn(III), Mn(IV), and chemical bath deposited MnO2 in powder form in the lead adsorption.

Nanotubes with anatase nanoparticulate walls obtained from NH4TiOF3 nanotubes prepared by anodizing Ti

In this work, titanium dioxide nanoparticulate nanotubes (NP-NT) in anatase phase from ammonium oxyfluorotitanate nanotubes (NT NH₄TiOF₃) are shown.