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Three types of biomass of invasive plants and agrowastes, namely, the wattle bark of Acacia auriculiformis (BA), mimosa (BM), and coffee husks (BC), were converted into biochars through slow pyrolysis and investigated for their ability to remove dyes in water. The properties of the materials were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis. The BET surface area (total pore volume) of BC was 2.62 m2/g (0.007 cm3/g), far below those of BA and BM with 393.15 cm2/g (0.195 m3/g) and 285.53 cm2/g (0.153 m3/g), respectively. The optimal adsorption doses for the removal of methylene blue (MB) were found to be 2, 5, and 5 g/L for BC, BA, and BM, respectively. The suitable pH ranges for MB removal were 6–12 for BA, 7–12 for BC, and 2–10 for BM. The majority of MB (over 83%) was removed in the initial 30 min, followed by a more quasisteady state condition after the removal rate exceeded 90%. The experimental data were fitted with the kinetic models (PFO, PSO, Bangham, IDP), indicating that physicochemical adsorption, pore diffusion process, and multiple stages are the dominant mechanisms for the MB adsorption onto biochars. Finally, BA and BM showed similar adsorption efficiencies, while BC may not be favorable for use as an adsorbent due to its low surface area and low pore volume.

Over the last several decades, the frequent occurrence of algal bloom in drinking water supplies, driven by increasing anthropogenic input and climate change, has posed serious problems for membrane filtration processes, resulting in reduced membrane permeability and increased energy consumption. It is essential to comprehensively understand the characteristics of algal dissolved organic matter (DOM) and the subsequent effects on the filtration processes for better insight into membrane fouling mitigation. Many studies have revealed that algal DOM has displayed unique characteristics distinguished from other sources of DOM with respect to the chemical composition, the structures, and the molecular weight distributions. Algal DOM is considered to be a major obstacle in understanding membrane fouling due to its complicated interactions among dissimilar algal DOM constituents as well as between algal DOM and membrane material matrices. The present review article summarizes (1) recent characterizing methods for algal DOM, (2) environmental factors affecting the characteristics of algal DOM, (3) the discrepancies between algal DOM and other sources of aquatic DOM, particularly terrestrial sources, and (4) potential fouling effects of algal DOM on membrane filtration processes and their associations with algal DOM characteristics. A broad understanding of algal DOM-driven membrane fouling can lead to breakthroughs in efficient membrane filtration processes to treat algal bloom water sources.