Optimizing singly-charged electrosprayed particle throughput of an electrospray aerosol generator utilizing a corona-based charger
Abstract
The performance of a needle tungsten corona-discharge charger (NTCC) as a neutralizer in an electrospray aerosol generator (EAG) is compared to that of a surface-discharge micro-plasma aerosol charger (SMAC). We demonstrate the performance of an EAG with a reduction chamber that consists of a neutralizer. The ion produced by the neutralizer is characterized by measuring its ion properties utilizing an ion counter, a Faraday cup electrometer, and a mini-cyDMA. Both the SMAC and NTCC have balanced bipolar ions with ion concentration ratios of 0.95 and 1.07, respectively. While the diffusivity of the positive ions produced by the NTCC is more significant than that of the SMAC, it is the opposite for negative ions. The EAG system is evaluated by optimizing the EAG orifice diameter and carrier airflow rate. It was found that a maximum singly charged electrosprayed particle could be achieved at an orifice diameter and a carrier airflow rate of 10 mm and 1 L min−1, respectively. The performance of charge reduction is determined by a multiply to singly charged ratio. The NTCC neutralizer dramatically reduced the highly charged electrosprayed particle to below 10 elementary charges. In brief, the result shows that the NTCC performs better than the SMAC in reducing multiply charged particles.