Adsorption of dimethyl trisulfide from aqueous solution on a low-cost adsorbent:thermally activated pinecone

Thermally activated pinecone(TAP) was used for the adsorption of dimethyl trisulfide(DMTS)from aqueous solutions,which was proved to be the main odorous in algae-caused black bloom.The effects of adsorbent dosage,adsorbate concentration and contact time on DMTS biosorption were studied.The TAP produced at 600℃ exhibited a relatively high surface area(519.69 m^2/g) and excellent adsorption capacity.The results show that the adsorption of DMTS was initially fast and that the equilibrium time was6 h.Higher initial DMTS concentrations led to lower removal percentages but higher adsorption capacity.The removal percentage of DMTS increased and the adsorption capacity of TAP decreased with an increase in adsorbent dosage.The adsorption process conforms well to a pseudo-second-order kinetics model.The adsorption of DMTS is more appropriately described by the Freundlich isotherm(R^2=0.996 1) than by the Langmuir isotherm(R^2=0.916 9).The results demonstrate that TAP could be an attractive low-cost adsorbent for removing DMTS from water.

Experimental and theoretical investigation on degradation of dimethyl trisulfide by ultraviolet/peroxymonosulfate: Reaction mechanism and influencing factors

With a large amount of domestic sewage and industrial wastewater discharged into the water bodies,sulfur-containing organicmatter inwastewater produced volatile organic sulfide,such as dimethyl trisulfide(DMTS)throughmicroorganisms,caused the potential danger of drinking water safety and human health.At present,there is still a lack of technology on the removal of DMTS.In this study,the ultraviolet/peroxymonosulfate(UV/PMS)advanced oxidation processes was used to explore the degradation of DMTS.More than 90%of DMTS(30μg/L)was removed under the conditions of the concentration ratio of DMTS to PMS was 3:40,the temperature(T)was 25±2℃,and 10 min of irradiation by a 200 W mercury lamp(365 nm).The kinetics rate constant k of DMTS reacting with hydroxyl radical(HO·)was determined to be 0.2477 min^(−1).Mn^(2+),Cu^(2+)and NO_(3)^(-)promoted the degradation of DMTS,whereas humic acid and Cl-in high concentrations inhibited the degradation process.Gas chromatography-mass spectrometry was used to analyze the degradation products and the degradation intermediates were dimethyl disulfide and methanethiol.Density functional theory was used to predict the possible degradation mechanism according to the frontier orbital theory and the bond breaking mechanism of organic compounds.The results showed that the S–S,C–S and C–H bonds in DMTS molecular structure were prone to fracture in the presence of free radicals,resulting in the formation of alkyl radicals and sulfur-containing radicals,which randomly combined to generate a variety of degradation products.