Liu Yang,Zhang Yuchen,Xie Tao,Yue Ming,Wang Dongsen,Li Bin
In light of the difficulty of solid-liquid separation of waste PEM drilling fluid in the Bohai oilfield, constructing an inorganic-organic flocculation system is proposed and the processing method of destabilization technology is optimized. The biggest influence factor on the flocculation process of PEM drilling fluid was determined by designing an orthogonal test. The flocculation mechanism was researched through single factor optimization, combined with zeta potential and particle size distribution test. The results showed that the most significant factors affecting the flocculation of waste PEM drilling fluid were the dosage of inorganic flocculant CaCl2 and flocculation pH value. When the dosage of inorganic flocculant CaCl2 was 1.2% (w/v), the dosage of organic flocculant SDYJ-2 was 0.05%, the flocculation pH value was 3, and the flocculation time was 5 min, the flocculation technology reached the optimization and then the liquid yield can reach 70.96%. The mechanism of flocculation and destabilization was as follows: the inorganic flocculant of CaCl2 mainly reduced the zeta potential of clay particles through electric neutralization. 1% CaCl2 could reduce the potential mean value of drilling fluid system from -38.1 mV to -32.5 mV, and then decrease the repulsion among suspensions. Through bridging curling and electric neutralization, the organic flocculant of SDYJ-2 can absorb and wrap the clay particles after flocculation destabilization to form a network spatial structure, which made clay particles aggregate into large flocs and particles. D50 can increase by 21.5 times, when the concentration of SDYJ-2 was 0.15%.
The residual antibiotics in the environment will pose a threat to the environment and human health. Thus, it is imperative to develop a smart water treatment material to remove and detect antibiotics from aqueous environment simultaneously. In this study, magnetic Cu–Ni–S@Ni foam was synthesized by liquid phase vulcanization method to in-situ load Cu–Ni–S nanostructures on the surface of Ni foam. The novelty of this material is the combination of adsorption-flocculation technology and semi-quantitative detection technology. Batch experiments showed that Cu–Ni–S@Ni foam has a high removal rate of norfloxacin (NOR) (96.92%), wide pH adaptability (pH = 4.0–10.0) and strong ion interference resistance (0.1–100 mmol/L). According to the Langmuir isotherm , the removal capacity can reach 417.4 mg/g at 25 °C, which is much higher than that of other water treatment agents reported in most studies. Characterization analysis indicated that the main removal mechanisms are surface complexation, cation bridging, electrostatic attraction , precipitation and flocculation . Transmission FTIR detection experiments showed that NOR on Cu–Ni–S@Ni foam has easily recognizable FTIR fingerprints; the intensity of characteristic peaks roughly reflects the concentration information of NOR to some extent. This semi-quantitative detection method, requiring simple operation without the fabrication of KBr tablet, has a wide linear range (5–100 mg/L) and a low limit of detection (4.6 mg/L). Therefore, Cu–Ni–S@Ni foam can be used for simultaneous removal and semi-quantitative detection of NOR in wastewater. It has potential application value in wastewater treatment and water quality monitoring.
Nowadays, the polymer flocculation technology has been widely used in the treatment of oil sand tailings pollutants. However, the most commonly used polyacrylamide flocculant has encountered some problems, such as low flocculation efficiency and severe secondary pollution. In this paper, an organic-inorganic composite high-efficiency flocculant with self-degradation was designed and prepared. Furthermore, in order to analyze the synthesis mechanism of the composite material, the functional groups of the material were investigated by Fourier transform infrared spectroscopy (FTIR). At the same time, the morphology and structure were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Meanwhile, the crystal structure was recorded by XRD . In addition, the flocculation efficiency of the composite flocculant was determined by measuring the turbidity removal of the kaolin suspension. Apart from this, the flocculation parameters were optimized by central composite design (CCD) experimental design and response surface methodology (RSM). Finally, the self-degrading property of the flocculant was tested under light conditions. The characterization data of the material indicated that the synthesis mechanism is that under the ultraviolet light condition, the acrylamide monomer undergoes free radical polymerization under the action of active free radicals on the surface of the core-shell structure SiO 2 -TiO 2 to form an organic-inorganic composite flocculant. In addition, the optimized experimental results showed that the optimal turbidity removal conditions were followed: V TBOT /m SiO2 of 6.66 mL/g, flocculant dosage of 50 ppm and kaolin suspension concentration of 1.5 wt%. Ultimately, the degradation experiment showed that the prepared organic-inorganic composite flocculant has nice self-degradation performance, and the self-degradation efficiency reaches over 90% within two hours. In summary, this work has greatly enriched the knowledge of oil sand tailings treatment.
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