Diffusion-controlled Algaecide Release Technology

Diffusion-controlled Algaecide Release Technology (DART) is an experimental controlled-release platform that regulates the sustained diffusion of algaecides from an internal reservoir into aquatic environments through hydrogel diffusion elements.¹ Unlike conventional controlled-release systems that incorporate the active compound into the carrier material, DART stores the treatment agent in a refillable internal reservoir while the hydrogel functions as a diffusion barrier that regulates mass transport. Release rates can be adjusted by modifying the geometry or composition of the hydrogel diffusion elements.¹

DART was developed by researchers at the University of Toledo as part of a research program supported by the United States Army Corps of Engineers investigating sustained treatment strategies for freshwater harmful algal blooms (HABs).² The first reported implementation of the technology was a hydrogel-based floating buoy for the sustained delivery of hydrogen peroxide to mitigate harmful algal blooms.³

The technology integrates principles of diffusion-controlled mass transport, hydrogel engineering, and controlled-release technology to provide sustained delivery of treatment agents in aquatic environments.¹

DART operates through diffusion-controlled mass transport. The active agent is stored in an internal reservoir and diffuses through hydrogel diffusion elements into the surrounding water under a concentration gradient. Rather than functioning as a carrier for the active compound, the hydrogel acts as a diffusion barrier that regulates the transport rate between the reservoir and the external environment.¹

According to the published mathematical model, the release kinetics are governed by the physicochemical properties of both the hydrogel and the active agent, as well as by geometric parameters including the hydrogel thickness, exposed surface area, and diffusion path length. These variables can be adjusted to modify the release profile while maintaining the same overall platform architecture.¹

The first reported application of DART was the sustained delivery of hydrogen peroxide for freshwater harmful algal bloom mitigation using a hydrogel-based floating buoy.¹ Because the technology regulates the diffusion of an active agent from an internal reservoir rather than relying on the carrier material itself as the storage matrix, the same platform could potentially be adapted for the controlled delivery of other treatment agents. As of 2026, however, published studies have focused primarily on hydrogen peroxide.¹

Compared with conventional controlled-release formulations in which the active compound is incorporated directly into the carrier material, DART physically separates the treatment agent from the hydrogel diffusion element. This design allows the internal reservoir to be replenished without replacing the hydrogel and permits release characteristics to be modified by changing the geometry or composition of the diffusion elements.¹

The modular design also enables different release profiles to be obtained using the same platform architecture by varying hydrogel dimensions or physicochemical properties rather than altering the reservoir configuration.¹

As of 2026, DART remains an experimental technology. Published evaluations have primarily consisted of laboratory release studies and mesocosm experiments investigating hydrogen peroxide for the mitigation of freshwater harmful algal blooms.¹

Additional field validation under diverse environmental conditions is needed to evaluate long-term performance, operational durability, and applicability at larger spatial scales. Furthermore, the technology has so far been reported primarily for hydrogen peroxide delivery, and its performance with other treatment agents has not yet been extensively investigated in the published literature.¹