Yucheng Liu

Adsorption characteristics and mechanism of sewage sludge-derived adsorbent for removing sulfonated methyl phenol resin in wastewater

Sulfonated methyl phenol resin (SMP) is one of the most popular organic additives in drilling fluid. It is difficult to treat drilling wastewater that contains SMP. Sewage sludge-derived adsorbent (SSA) was prepared by pyrolysis and activation of sewage sludge. Compared to other biochar and bentonitic adsorbents, the SSA possessed the highest adsorption capacity for SMP, with a removal capacity of 39.41 mg g−1. The adsorption of SMP onto SSA was investigated by pH, ionic strength, SMP initial concentration, contact time and temperature. The Langmuir and Freundlich isotherm models were used to describe the adsorption equilibrium. The Langmuir monolayer adsorption capacity of SSA was estimated as 42.97 mg g−1. The pseudo-first-order kinetic, pseudo-second-order kinetic and intra-particle diffusion kinetic model were employed to analyze the adsorption process of SMP onto SSA. The adsorption activation energy (Ea) was 23.95 kJ mol−1 at 25–40 °C, which implied the physisorption was more significant in the SMP–SSA system. The adsorption thermodynamics was evaluated, and the parameters such as the enthalpy (ΔH0) was 14.41 kJ mol−1 and entropy (ΔS0) was 58.64 J mol−1 K−1 at 100 mg L−1 SMP. The results indicated the SMP adsorption onto SSA was spontaneous and endothermic in nature. The excellent adsorption capacity for SMP indicates that the SSA could be a new promising low cost adsorbent for removal of SMP pollutants in drilling wastewater.

Grey relational analysis of contaminants governing foaming behavior in desulfurization solution for high-sulfur natural gas

ABSTRACT The priorities of contaminants governing foaming in the 50 wt% methyldiethanolamine (MDEA) were investigated in this study. On the basis of the standard ASTM D892, the foam height and foaming break time of the MDEA solution with the addition of thirteen different concentration contaminants were measured. Grey relational analysis method was used to identify the influential priorities of each contaminant on the foaming behavior. Results indicated that the most important controllable contaminations on the foaming behavior, in sequence, were ferrous ion (Fe2+), N,N-bis(2-hydroxyethyl)glycine (Bicine) and triethanolamine (TEA). The research results would facilitate the solution foaming control in natural gas purification field.

Adsorptive desulfurization of thiophene from the model fuels onto graphite oxide/metal-organic framework composites

ABSTRACT The composites of a copper-based metal-organic framework (HKUST-1) in the presence of graphite oxide (GO) were synthesized via a solvothermal method to remove thiophene (TP). The prepared GO/HKUST-1 composites were characterization by N2 adsorption-desorption, XRD, SEM. The desulfurization performance of TP from the model fuels by GO/HKUST-1 with different content of GO was investigated. Most importantly, under the optimum adsorptive conditions, the composite material 1.75%GO/HKUST-1 exhibited excellent adsorption capacity of 60.67 mg/g, which was attributed to the highest surface area and porosity.

Production of a bioflocculant from Klebsiella sp. OS-1 using brewery wastewater as a source

ABSTRACT This study evaluated the potential of bioflocculant production from a Klebsiella strain using brewery wastewater as nutrients. The bioflocculant named OS-1B produced by Klebsiella sp. OS-1 exhibited a good flocculating activity to kaolin clay suspension (around 95%), when the diluted brewery wastewater with 7.2 mg/L total nitrogen and 1013 mg/L CODCr was used as a nitrogen source. Glucose (15 g/L) is the most favorable carbon source for Klebsiella sp. OS-1 in bioflocculant production from brewery wastewater. The yielded bioflocculant is pH tolerant and thermally stable, suggesting its good industrial potential. OS-1B mainly comprises polysaccharide (69.4%) and protein (24.5%). Fourier-transform infrared spectra indicate the presence of hydroxyl, carboxyl, esters and amino groups in the bioflocculant molecules. Combined with the results of zeta potential measurements, bridging is suggested as the main flocculation mechanism for OS-1B flocculation with kaolin. Overall, brewery wastewater can be used as a substrate to produce bioflocculants.

Influence of Salt Impurities on Foaming Properties of MDEA Desulfurization Solution

The influence of salt impurities on foaming of N-methyldiethanolamine (MDEA) solutions was studied. Studies of the influence of individual ions on foaming of fresh MDEA solution showed that Ca2+, Fe2+, Mg2+, and Sr2+ tended to induce foaming and stabilize the foam. The effects of the cations followed the order Fe2+ > Sr2+ > Mg2+ > Ca2+. The anions F–, CH3COO–, HCOO–, Cl–, Br–, SO42–, C2O42–, S2O32–, and SCN– exerted a slight inhibitory effect on foaming. The order of the tendency to induce foaming changed to Sr2+ > Mg2+ > Fe2+ > Ca2+ if these ions were present simultaneously in the solution. Ca2+ enhanced significantly the tendency to induce foaming but had no effect on the foam stability. Fe2+ and Sr2+ had a synergic effect on the tendency to induce foaming and stabilize the foam.