Modification of Zero Valent Iron Nanoparticles by Sodium Alginate and Bentonite: Enhanced Transport, Effective Hexavalent Chromium Removal and Reduced Bacterial Toxicity

<p>The rapid aggregation/sedimentation and decreased transport of nanoscale zero-valent iron (nZVI) particles limit their application in groundwater remediation. To decrease the aggregation/sedimentation and increase the transport of nZVI, sodium alginate (a neutral polysaccharide) and bentonite (one type of ubiquitous clay) were employed to modify nZVI. Different techniques were utilized to characterize the modified nZVI. We found that modification with either sodium alginate or bentonite could disperse the nZVI and shifted their zeta potentials from positive to negative. Comparing with the bare nZVI, the sedimentation rates of modified nZVI either by sodium alginate or bentonite are greatly decreased and their transport are significantly increased. The transport of modified nZVI can be greatly increased by increasing flow rate. Furthermore, Cr(VI) can be efficiently removed by the modified nZVI (both sodium alginate and bentonite modified nZVI). Comparing with bare nZVI, the two types of modified nZVI contain lower toxicities to Escherichia coli. The results of this study indicate that both sodium alginate and bentonite can be employed as potential stabilizers to disperse nZVI and improve their application feasibility for in situ groundwater remediation.</p>

Challenges and opportunities of pH in chronic wounds

Regarded as a silent epidemic, chronic wounds are a global public health issue. Wound healing is a complex, synchronized cascade of physiological processes restoring the anatomic and functional integrity of the skin; however, chronic wounds fail to proceed through the wound healing cascade. Wound pH oscillates during wound healing, usually traversing from a neutral pH to an acidic pH, while chronic wounds perpetuate in an elevated alkaline milieu. Although a neglected clinical parameter, pH has implications for relatively all pathologies of wound healing affecting oxygen release, angiogenesis, protease activity, bacterial toxicity and antimicrobial activity. Despite the array of wound healing products currently marketed, understanding the implications of pH on arresting wound healing can stimulate innovation within this vast market.

Bacterial toxicity of biomimetic green zinc oxide nanoantibiotic: insights into ZnONP uptake and nanocolloid–bacteria interface

Growth and biofilm inhibitory action of biomimetic green ZnONPs and dissolved zinc ions on a bacterial interface.