• Membrane Journal
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• v.24 no.6
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• pp.431-437
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• 2014

To overcome the flux reduction due to the fouling by adsorption of foulants onto the porous hydrophobic polyethylene membrane surface, the oxyflorination was introduced to hydrophilize the hydrophobic membranes. After the hydrophilization through oxyfluorination, the contact angle decreased from $93^{\circ}$ to $50^{\circ}$ while the water flux increased to 60%. It was considered that for the model foulants dissolved in water, such as albumin (form bovine serum, BSA), humic acid sodium salt (HA), and alginic acid sodium salt (SA), the flux was enhanced since the adsorbed foulants decreased by the oxyfluorination. Particularly, it was obtained that the water flux was over twice more than the untreated polyethylene membrane in case of SA foulant.

• Membrane Journal
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• v.22 no.6
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• pp.481-488
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• 2012

The anionic exchange polymer, poly(vinyl amine)(PVAm), was coated onto polyamide (PA) reverse osmosis (RO) membranes by using 'salting-out' method. The effects of the fouling phenomena for these PVAm coated membranes were investigated using the model foulants, bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA). The surface coating and the fouling phenomena were observed by the scanning electron microscopy. And the flux was measured for each 100 ppm of above foulant aqueous solution at the operating pressure, 2, 4, 8 bar. The PVAm-coated PA membranes showed somewhat fouling improvements and the fouling reduction was shown in the order of HA > SA > BSA, particularly HA case was distinct.

• Membrane Journal
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• v.29 no.5
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• pp.276-283
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• 2019

In this study, The experiments of the confirmation of the fouling phenomena in CDI process and the establishment of its removal process conditions were carried out. The foulant concentrations of humic acid sodium salt (HA) added to the feed solution were 5, 10, 15 mg/L, respectively. The occurrence of fouling under the certain adsorption/desorption conditions could be confirmed with an increase in adsorption and desorption concentration curve over time. Both the voltage and time in adsorption and desorption processes were changed to eliminate the fouled pollutants. Typically, the fouling removal condition was found at the adsorption condition 1.2 V/5 min and the desorption condition -3 V/2 min, respectively.

• Molecules and Cells
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• v.40 no.12
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• pp.966-975
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• 2017

Excessive salt disrupts intracellular ion homeostasis and inhibits plant growth, which poses a serious threat to global food security. Plants have adapted various strategies to survive in unfavorable saline soil conditions. Here, we show that humic acid (HA) is a good soil amendment that can be used to help overcome salinity stress because it markedly reduces the adverse effects of salinity on Arabidopsis thaliana seedlings. To identify the molecular mechanisms of HA-induced salt stress tolerance in Arabidopsis, we examined possible roles of a sodium influx transporter HIGH-AFFINITY $K^+$ TRANSPORTER 1 (HKT1). Salt-induced root growth inhibition in HKT1 overexpressor transgenic plants (HKT1-OX) was rescued by application of HA, but not in wild-type and other plants. Moreover, salt-induced degradation of HKT1 protein was blocked by HA treatment. In addition, the application of HA to HKT1-OX seedlings led to increased distribution of $Na^+$ in roots up to the elongation zone and caused the reabsorption of $Na^+$ by xylem and parenchyma cells. Both the influx of the secondary messenger calcium and its cytosolic release appear to function in the destabilization of HKT1 protein under salt stress. Taken together, these results suggest that HA could be applied to the field to enhance plant growth and salt stress tolerance via post-transcriptional control of the HKT1 transporter gene under saline conditions.