POLYMERIC COMPOSITION FOR PURIFICATION OF WASTEWATER FROM VARIOUS IMPURITIES IN TEXTILE INDUSTRY

This article deals with the development of new and improvement of traditional methods of wastewater treatment of dyening and finishing industries. The composition was developed on the basis of local natural minerals (bentonite Navahermosa origin, sodium bisulfite, polyacrylamide and aluminium sulphate) for the treatment of wastewater of the textile industry. The influence of bentonite particle size on the degree of wastewater discoloration at different flow rates was studied. With a range of wastewater supply flow rates from 0.5 to 2.0 m/s with a particle size of bentonite adsorbent in the range of 0.25-1.0 nm, the maximum degree of wastewater bleaching is achieved and it is in the range of 84-87%. For microporous adsorbents (CAD-100 and CAD-200) the effectiveness of the discoloration also does not depend on the particle size and ranges from 85 to 87 %. It was found that, for fine-pored adsorbents (BKA-100 and BKA-200), the efficiency of discoloration also practically does not depend on the particle size and ranges from 85 to 87 %. The highest degree of wastewater treatment according to the proposed composition, apparently due to the fact that in the adsorption process, in addition to the sorption of sewage impurities on the surface of adsorbents, there is a sorption of ions and molecules of dissolved substances on the surfaces of air bubbles and their removal in the foam layer. The wastewater treatment parameters of the dyeing and finishing shop using the bentonite composite adsorbent show that the degree of removal of contaminants by the method developed by us is much higher compared to the sedimentation of aluminum or iron oxyhydrates with adsorbed contaminants. Moreover, the effects of reducing the value of COD and concentration of the surfactant in the wastewater was, on average, 65 % and 82 %, and compared to the effects of reducing the same parameters at defending precipitation of oxyhydrates at 48-54 % and 54-61 %, respectively.

Preparation and Application of a New Crosslinked Polyammonium as a Shale Inhibitor

Background: Despite the fact that a number of traditional shale inhibitors have been utilized widely in drilling operations, the same additive may be unfavorable for different drilling due to environmental protection requirements which limit scales of use. Hence, a series of polyammonium compounds was prepared from dimethylamine, epichlorohydrin, and melamine (DEM). Methods: To concentrate our efforts, we used both standard and extra methods to investigate the inhibitive properties of a melamine crosslinking agent using mud balls immersion tests, linear expansion measurements, laser particle distribution measurements, thermogravimetric analysis, and scanning electron microscopy. Results: The anti-swelling rate of DEM-8 reached up to 92.3% when its concentration reached 0.8%. DEM-8 has strong inhibitive capability to bentonite hydration swelling. DEM-8 can affect the bentonite particle size at a large scale. It may adsorb on the surface of clay through hydrogen bonds and electrostatic interaction by an anchoring effect and a hydrophobic effect. Conclusions: Compared with a blank solution, DEM-8 displays high inhibitive ability against the hydration and swelling of clay. The mud ball is more stable in DEM-8 solution and its swelling degree is very low compared with that of the control test. The inhibition mechanism of DEM-8 to shale can be deduced in that hydrogen bonding, ion exchange, and anchoring effect help to control the hydration and swelling.

BENTONITE-QUARTZ SAND AS THE BACKFILL MATERIALS ON THE RADIOACTIVE WASTE REPOSITORY

An investigation of the contribution of quartz sand in the bentonite mixture as the backfill materials on the shallow land burial of radioactive waste has been done. The experiment objective is to determine the effect of quartz sand in a bentonite mixture with bentonite particle sizes of -20+40, -40+60, and -60+80 mesh on the retardation factor and the uranium dispersion in the simulation of uranium migration in the backfill materials. The experiment was carried out by the fixed bed method in the column filled by the bentonite mixture with a bentonite-to-quartz sand weight percent ratio of 0/100, 25/75, 50/50, 75/25, and 100/0 on the water saturated condition flown by uranyl nitrate solution at concentration (Co) of 500 ppm. The concentration of uranium in the effluents in interval 15 minutes represented as Ct was analyzed by spectrophotometer, then using Co and Ct, retardation factor (R) and dispersivity () were determined. The experiment data showed that the bentonite of -60+80 mesh and the quartz sand of -20+40 mesh on bentonite-to-quartz sand with weight percent ratio of 50/50 gave the highest retardation factor and dispersivity of 18.37 and 0.0363 cm, respectively. Keywords: bentonite, quartz sand, backfill materials, radioactive waste

Application of Clay for Petrochemical Wastewater Pretreatment

Petrochemical industry wastewater is contaminated with nitrogen and phosphorous compounds, mainly ammonium and ammonium nitrogen, and therefore needs treatment before it is released in the watercourse. Usually, petrochemical wastewater treatment is carried out following the ion exchange principle. One of the possibilities of petrochemical wastewater pretreatment is using bentonite clays. Bentonite decreases the concentration of ions in the incoming wastewater and, as a consequence, the ion exchanger placed subsequently works more efficiently. The experiment was carried out with alkali-activated granulated bentonite and acid-activated granulated bentonite. In this work, bentonite particle size, the quantity and the type of bentonite, as well as the time of the contact of bentonite and wastewater were optimized. It was found that the highest percentage of ion removal of 83% for ammonia ions and 71% for phosphate ions was accomplished when the model solution was treated with a mixture of acid- and alkali-activated bentonite for 5 minutes.

Erosion Properties and Dispersion-Flocculation Behavior of Bentonite Particles

Experimental and theoretical studies have been performed to clarify the ability of flowing groundwater in contact with bentonite to generate bentonite colloidal particles and disperse such colloids. This information is required to determine (a) the long-term stability of bentonite as a buffer material for borehole disposal of radioactive wastes in deep geologic media and (b) the potential influence of bentonite colloidal particles on radionuclide transport, specifically for use in scenario analyses in the performance assessment of waste disposal.In this study, the minimum groundwater velocity required to erode particles of Nabentonite or Ca-bentonite from a bentonite surface in contact with groundwater was derived from shear strengths of aqueous bentonite gel suspensions, as determined by viscometer tests. The shear strengths were used to estimate the corresponding shear force on bentonite particle-particle bonds, using an estimated value for the number of initial bentonite particle-particle bonds in the experimental systems studied. The derived shear force was converted to corresponding groundwater velocity by using Stokes' equation and simplifying assumptions. The results indicate that groundwater velocities in a range of about 10−5 to 10−4 m/s would be required to initiate bentonite erosion. This range is higher than the groundwater flow velocity generally found in deep geologic media in Japan. In addition, known groundwater electrolyte concentrations were compared with theoretical estimates of aqueous electrolyte concentrations required to flocculate colloidal bentonite particles (for example 1 × 10−3 mol/l Na+). The comparison indicates that, even if erosion of bentonite occurred, the colloidal bentonite particles formed would flocculate. As a result, this study has shown that the effect of bentonite colloids on radionuclide transport is likely to be negligible in the performance assessment of radioactive waste disposal in deep geologic media.