No abstract

Magnetite nanoparticles (MNPs) Fe3O4 and r-Fe2O3 were surface-modified with poly(ethylene glycol) (PEG) in order to improve their specificity and bioactivity. PEG and the anti-MEL monoclonal antibody (mAb) were successfully immobilized on the surface of MNPs and characterized using FTIR, UV-Vis and TEM analyses. Surface modification of MNPs-PEG-mAb conjugates of a variety of sizes and magnetite types was employed to design and prepare labels for use in a lateral flow immunoassay (LFIA) to test whether the size of the conjugate can affect the performance of the assay. The results showed that the detection limit was mainly determined by the size of the MNPs-PEG-mAb conjugate. Under optimized conditions, a detection limit of 0.4 ppm for melamine was achieved using Fe2O3-PEG-mAb, which was almost 5-fold lower than that of the Fe3O4-PEG-mAb conjugate (2.2 ppm).

A colloidal silver nanoparticle (AgNP)-based lateral flow immunoassay (LFIA) was evaluated in terms of the rapid detection of profenofos (PEO) pesticide residue in vegetables.

No abstract

The applications of membrane processes in anaerobic biological wastewater treatment still have some limitations due to severe membrane scaling and fouling, although they have been proven to achieve superior COD removal and biomass retention. An innovative anaerobic membrane process for wastewater treatment was conducted to control the membrane scaling problems. The process comprises an anaerobic reactor, an aerobic reactor, and a membrane separation tank. Anaerobic sludge from a full-scale UASB reactor treating food wastewater was inoculated to anaerobic and aerobic reactor to purify synthetic wastewater consisting of glucose and sodium acetate. The anaerobic reactor was operated in a sludge bed type without three-phase separator. The aerobic reactor can eliminate residual organics from the anaerobic reactor effluent using facultative microorganisms. To provide solid-liquid separation, hollow fiber ultrafiltration module was submerged in the separation tank. The results clearly show that the anaerobic membrane process combined methanogenic and aerobic COD reduction is a stable system. No fatal scaling was found after two months of operation even without chemical cleaning for the membrane. It was also found that inorganic precipitates formed in the aerobic reactor were reduced due to CO2 stripping in aerobic reactor. Another important finding was that the inorganic precipitates were entrapped into facultative aerobes floc. The ash/SS ratio of aerobes floc increased from 0.17 to 0.55 after 50 days of operation, which confirms this phenomenon. Based on our investigation, the new process can control scaling effectively to extend the membrane application in anaerobic treatment.