Influence of Functional Group Modification on the Toxicity of Nanoplastics

Nanoplastics (NPs) are ubiquitous in harvested organisms at various trophic levels, and more concerns on their diverse responses and wide species-dependent sensitivity are continuously increasing. However, systematic study on the toxic effects of NPs with different functional group modifications is still limited. In this review, we gathered and analyzed the toxic effects of NPs with different functional groups on microorganisms, plants, animals, and mammalian/human cells in vitro. The corresponding toxic mechanisms were also described. In general, most up-to-date relevant studies focus on amino (−NH2) or carboxyl (−COOH)-modified polystyrene (PS) NPs, while research on other materials and functional groups is lacking. Positively charged PS-NH2 NPs induced stronger toxicity than negatively charged PS-COOH. Plausible toxicity mechanisms mainly include membrane interaction and disruption, reactive oxygen species generation, and protein corona and eco-corona formations, and they were influenced by surface charges of NPs. The effects of NPs in the long-term exposure and in the real environment world also warrant further study.

Modifikasi Kotak Polistiren untuk Penyimpanan Dingin Sayur Kubis dengan Menggunakan Es Kering sebagai Media Pendingin

ABSTRAK Penelitian telah dilakukan pada kotak modifypolystyrene sebagai kotak pengiriman kubis segar menggunakan es kering sebagai media pendingin. Penelitian ini bertujuan untuk menguji kotak yang dimodifikasi untuk mengetahui kotak yang paling cocok dimodifikasi untuk menjaga kesegaran sayuran. Kotak polystyrene yang dimodifikasi dibuat dengan memisahkan kotak menjadi dua kompartemen, satu kompartemen untuk menempatkan es kering sebagai media pendingin, dan kompartemen lain untuk menyimpan kubis segar. Itu dibuat lima jenis kotak dimodifikasi, dua jenis media pendinginan mondar-mandir di bawah sayuran segar, sedangkan jenis sisanya menempatkan media pendingin di atas sayuran. Tes yang dilakukan selama 7 jam terdiri dari suhu di sekitar kotak, suhu di dalam kotak, dan suhu pusat kubis segar. Pengukuran lain yang dilakukan adalah berat es kering yang digunakan selama penyimpanan dingin, penurunan berat kubis segar, pengamatan visual kerusakan kubis segar, dan perhitungan keseimbangan energi. Menempatkan es kering di bawah kubis segar menyebabkan suhu tengah kubis segar jauh di atas suhu penyimpanan yang disarankan, 0oC, sementara menempatkan media pendingin di atas sayuran memberi dampak negatif pada sayuran di mana suhu tengah kubis segar di bawah 0oC untuk dua jenis kotak yang dimodifikasi, kecuali es kering yang ditempatkan di baskom yang terbuat dari piring zink. Berdasarkan perhitungan energi, terungkap bahwa hampir lebih dari 75% energi pendingin digunakan untuk mengatasi beban pendinginan di sekitarnya. Ditemukan bahwa kotak modifikasi yang paling cocok untuk menyimpan kubis segar adalah jenis kelima. ABSTRACT Research had been carried out to modify polystyrene box as fresh cabbage delivery box using dry ice as a cooling medium. The research aims were to find out the most suitable model box to maintain the freshness of the vegetables. Modified polystyrene box was made by separating the box into two compartments, one compartment for placing dry ice, and another compartment for storing the fresh cabbage. The box was modified into five types which consisted of two types of the box where the cooling medium was placed below the fresh vegetable, while for the rest, the cooling medium was placed above the vegetable. The tests were performed for 7 hours with the hourly observation that consisted of the temperature surrounding the model box, temperature inside the box, and temperature of the center of the fresh cabbage. Other conducted measurements were the weight of dry ice used during cold storage, weight loss of fresh cabbage, visual observation on the deterioration of the fresh cabbage, and energy equilibrium calculation. Placing dry ice below the fresh cabbage caused the center temperature of the fresh cabbage to far above the recommended storing temperature, 0oC, while placing the cooling medium above the vegetable gave a negative impact on the vegetable where the center temperature of the fresh cabbage was below 0oC for the two types of model boxes, except for the fifth type box where dry ice was placed in a basin made of zink plate. Based on energy calculation it was revealed that almost more than 75% of cooling energy was used to overcome the surrounding cooling load. It was found that the most suitable model box for storing the fresh cabbage was the fifth type.

Acetylation Modification of Waste Polystyrene and Its Use as a Crude Oil Flow Improver

Polystyrene is used in a wide range of applications in our lives, from machine housings to plastic cups and miniature electronic devices. When polystyrene is used, a large amount of waste is produced, which can cause pollution to the environment and even harm biological and human health. Due to its low bulk density (especially the foamed type) and low residual value, polystyrene cannot be easily recycled. Often waste polystyrene is difficult to recycle. In this paper, waste polystyrene has been modified by using acetic anhydride which caused a crude oil flow improver. The results showed that modified polystyrene improves the flow properties of the crude oil, reducing the viscosity and the pour point of the crude oil by up to 84.6% and 8.8 °C, respectively. Based on the study of the paraffin crystal morphology, the mechanism of improving the flow capacity of crude oil by modified polystyrene was proposed and analyzed.