Clean application of magnetic biomaterial for the removal of As (III) from water

Pine bark crosslinked to cyclodextrin for the adsorption of 2-nitrophenol from an aqueous solution

Adsorbents that are less expensive and more effective at removing organic micropollutants from wastewater have been developed through several approaches. Pine bark was treated with sodium hydroxide and then cross-linked to cyclodextrin using hexamethylene diisocyanate, in this study as an efficient adsorbent in the removal of 2-nitrophenol. FTIR, TGA and pHpzc analysis were used to characterize the biosorbent. The effects of pH, adsorbent mass, contact time and initial concentration on 2-nitrophenol removal was examined through batch adsorption studies. Pine bark crosslinked to cyclodextrin (PB-CD) surface functionalities was confirmed by FTIR analysis. It was discovered that solution pH, adsorbent mass, concentration and contact time all played a crucial role in the 2-nitrophenol uptake on PB-CD biosorbent and pine bark (PB) treated with sodium hydroxide. 2-Nitrophenol equilibrium was achieved with 0.05 g of adsorbents, with an initial concentration of 100–200 mg/dm3 at pH 5 after 60 min. The pseudo-second-order kinetic model and the Langmuir isotherm model significantly fitted the adsorption process. The Langmuir maximum capacities for PB and PB-CD were 47.36 mg/g and 77.82 mg/g, respectively. Overall, in the removal of 2-nitrophenol from an aqueous solution, PB-CD biosorbent is more cost-effective and efficient, in comparison with previously reported biosorbents in literature.

Optimization studies of BTX removal by magnetite coated oleic acid obtained from microwave-assisted synthesis using response surface methodology

Benzene, toluene and xylene (BTX) are volatile organic compounds released into the environment, that require urgent removal to avoid adverse health effects. In this work, the modelling and optimization of the preparation factors for magnetite coated oleic acid (MNP-OA) composite from microwave synthesis using response surface methodology were conducted to maximize BTX removal, and iron content. The influence of five crucial preparation variables: the Fe^3+/Fe²⁺ solution volumes, microwave power, volume of ammonia water (VAW), reaction time and volume of oleic acid (VOA) on the iron content (% Fe), and BTX adsorption capacity were investigated. The analysis of variance results revealed that VOA and VAW were the most influential factors for high % Fe content, and improved BTX removal. The % Fe, and BTX adsorption capacity for MNP-OA composite at optimized experimental conditions were estimated to be 85.57%, 90.02 mg/g (benzene), 90.07 mg/g (toluene), and 96.31 mg/g (xylene).

Treatment of aqueous arsenic - A review of biosorbent preparation methods

Arsenic (As) is a worldwide human health issue with the major exposure route being the consumption of As-contaminated drinking water. Sorption is considered to be an efficient treatment method, among other technologies, for As removal from various water and wastewater matrices. There are common commercially available sorbents, however, the use of locally or regionally available biomasses have recently been of interest as potentially cost-effective and environmentally friendly alternatives. Despite these benefits, untreated biomasses often show low sorption capacity, can be too fragile, and can lead to coloration of waters when used in treatment processes. Treatment methods of biomasses can include chemical processes using acid or alkaline solutions, developing of biomass composite by deposition of activating agents, and preparation of biochars. This review includes an overview of 53 recent studies that assess a variety of biomass modification methods meant to overcome these issues such as activation with acids or bases and biomass-based composites. Furthermore, future perspectives have been provided to assist in the further optimization of methods for biomass modifications to enhance their As sorption capacities.