Cleaner Approach for Atrazine Removal Using Recycling Biowaste/Waste in Permeable Barriers

This work addresses the rehabilitation of water contaminated with atrazine, entrapping it in a permeable and sustainable barrier designed with waste materials (sepiolite) and with biomaterials (cork and pine bark). Atrazine adsorption was assessed by kinetics and equilibrium assays and desorption was tested with different extraction solvents. Adsorbed atrazine was 100% recovered from sepiolite using 20% acetonitrile solution, while 40% acetonitrile was needed to leach it from cork (98%) and pine bark (94%). Continuous fixed-bed experiments using those sorbents as PRB were performed to evaluate atrazine removal for up-scale applications. The modified dose-response model properly described the breakthrough data. The highest adsorption capacity was achieved by sepiolite (23.3 (±0.8) mg/g), followed by pine bark (14.8 (±0.6) mg/g) and cork (13.0 (±0.9) mg/g). Recyclability of sorbents was evaluated by adsorption-desorption cycles. After two regenerations, sepiolite achieved 81% of atrazine removal, followed by pine with 78% and cork with 54%. Sepiolite had the best performance in terms of adsorption capacity/stability. SEM and FTIR analyses confirmed no significant differences in material morphology and structure. This study demonstrates that recycling waste/biowaste is a sustainable option for wastewater treatment, with waste valorization and environmental protection.

Effects of permeable barriers on total ecosystem carbon stocks of mangrove forests and abandoned ponds in Demak District, Central Java, Indonesia

Authors. 2020. Effects of permeable barriers on total ecosystem carbon stocks of mangrove forests and abandoned ponds in Demak District, Central Java, Indonesia. Biodiversitas 21: 5298-5307. In this study, we observed the effects of constructing permeable barriers in the low-lying coastal zone and severely eroded coast of Demak District, Central Java, Indonesia in the context of mangrove forest structures and carbon (C) dynamics. Forest structures were characterized by stand density, basal area, and ecological indices. The dynamics of C, expressed as total ecosystem carbon stocks (TECS), were compared in mangrove forests, abandoned ponds, and productive ponds by estimating C pools from above- and belowground biomass, dead organic matter, and soil. We found that permeable barriers, whether or not protect mangroves, results in the similarity of above- and belowground C due to no considerable difference in basal area. By contrast, soil properties in terms of bulk density, N concentration, and C:N ratio statistically varied among sites. We discovered that changes in soil properties were associated with duration of permeable barriers, resulting in an increase of soil C in mangrove sites, i.e., 618.84±30.39 Mg C ha−1; 704.13±17.73 Mg C ha−1; and 759.88±15.26 Mg C ha−1 in 0-, 1-, and 4-year-old permeable barriers, respectively. Moreover, these barriers were proved not only could enrich soil C in mangroves but also provide a habitat for Avicennia sp. seedlings in the newly reclaimed coastline.

Effects of calcium ion and pH on the adsorption/regeneration process by activated carbon permeable reactive barriers

Activated carbon (AC) is widely used in groundwater remediation, more specifically, for the activated carbon permeable barriers (AC-PRBs).

Solvent-dependent on/off valving using selectively permeable barriers in paper microfluidics

Non-mechanical on/off valving for paper microfluidics has been developed, based on solvent-dependent wettability and permeability of alkyl ketene dimer-patterned regions.