Softening of tap water via calcium removal using sphagnum peat moss sorbent by batch and flow-through approaches

ABSTRACT

The Gaza Strip experiences a water crisis of persistent qualitative and quantitative deterioration in regard to groundwater. There is a low recharging rate of the aquifer because of the low seasonal rainfall, the fast expansion of the urban area, and the high seawater intrusion along the narrow coastal Gaza Strip. Thus, the extremely hard water reduces the performance of the reverse osmosis desalination household units and causes membrane fouling. Sphagnum peat for removal of calcium from water was investigated applying batch and flow-through approaches. Fast calcium removal was demonstrated.     

Assessment of thermally treated sphagnum peat moss sorbents for removal of phenol red,bromothymol blue and malachite green from aqueous solution

Nine thermally treated sphagnum sorbents were investigated for dye removal of phenol red, bromothymol blue and malachite green from aqueous solutions. These sorbents were analysed for dye removal applying the optimum adsorption conditions with respect to shaking speed, equilibrium contact times and solution pH. The analysis applied the non-treated sphagnum sample. Furthermore, these sorbents were analysed by thermogravimetric analysis and infrared spectroscopy. Hence, sphagnum sorbents of mild or no thermal treatment were shown to remove very well both cationic and anionic dyes. This experiment has fortunately identified an economic method of low energy consumption for the treatment of dye effluents by sphagnum.     

Assessment of water quality in the vicinity of peat extraction sites: The case of Pien‐Saimaa,Finland

Peatlands have an important global role as carbon sinks. Locally, however, peat bog extraction can cause pollution in nearby watercourses. The aim of this study is to investigate the application of multivariate methods in the renovation and protection of eutrophic lakes surrounded by agricultural and peat extraction areas. The analytical data used in the study originated from a national water quality database and the period studied was 2000–2013. Multivariate methods: Principal Component Analysis (PCA) and Parallel Factor Analysis (PARAFAC) were applied to solve interactions of variables and pollution sources in a complex water ecosystem. Leaching from the peat bog area was found to be the main source of iron, which has an important role as a precipitator of phosphorus in loose sediment and in water. Nutrient ratios had no direct correlation to algae blooms, but high ratios indicated an increased likelihood of an upcoming bloom.     

Cadmium(II) and zinc(II) adsorption by the aquatic moss Fontinalis antipyretica: effect of temperature, pH and water hardness

The biosorption of cadmium(II) and zinc(II) ions onto dried Fontinalis antipyretica, a widely spread aquatic moss, was studied under different values of temperature, initial pH and water hardness. The equilibrium was well described by Langmuir adsorption isotherms. Maximum biosorption capacity of cadmium was independent on temperature and averaged 28.0 mg g(-1) moss, whereas for zinc, capacity increased with temperature, from 11.5 mg g(-1) moss at 5 degrees C to 14.7 mg g(-1) moss at 30 degrees C. Optimum adsorption pH value was determined as 5.0 for both metal ions. Cadmium uptake was unaffected by the presence of calcium ions, but zinc sorption was improved when water hardness increased from 101.1 to 116.3 mg CaCO(3)l(-1). Inversely, as hardness increases, the competition with calcium ions strongly reduces the affinity of the biosorbent for zinc.     

Multi-walled carbon nanotubes as solid-phase extraction adsorbents for determination of atrazine and its principal metabolites in water and soil samples by gas chromatography-mass spectrometry

A novel, simple, cost-effective, and sensitive method was developed for the determination of atrazine and its principal metabolites namely deisopropyl-atrazine (DIA) and deethyl-atrazine (DEA) in water and soil samples using multi-walled carbon nanotubes as solid-phase extraction (SPE) adsorbents coupled with gas chromatography-mass spectrometry (GC-MS). Several condition parameters, such as sample loading flow-rate, eluent and elution volume, extractant and ratio of extraction solvent to sample, were optimized to achieve good sensitivity and precision for the extraction and elution of analytes. A methanol/water solution (50%, v/v) was used to extract atrazine, DIA and DEA from soil. After the extracts went through SPE cartridges (packed with multi-walled carbon nanotubes) at a flow-rate of 4 mL min(-1), the analytes were eluted by 4 mL ethyl acetate at the rate of 1 mL min(-1) under a vacuum pump. The limit of detection (S/N=3) of the proposed method was 0.02 microg kg(-1) for atrazine in water and 0.3 microg kg(-1) in soil; 0.04 microg kg(-1) for DIA in water and 1.0 microg kg(-1) in soil; 0.05 microg kg(-1) for DEA in water and 0.8 microg kg(-1) in soil. Mean recoveries were in the range of 72.27-109.68%, and the reproducibility was accepted (RSD <13%) under the optimum conditions. This developed method was applied to determine the analytes in real environmental samples, and the concentrations of atrazine were 0.77-10.83 microg kg(-1), while DEA and DIA were not detected.