Study On Manufacture Of The Novel Bentonite-Plastics Adsorbent And Its Adsorption Properties

To exploit and utilize the bentonite of Ningming, Guangxi, and manufacture wastewater treatment adsorbents of bentonite with high efficiency, and solve its outstanding problems in the wastewater treatment, this paper brings forward that the bentonite will be granulated by using the plastic materials as the framework by the plastic manufacture technology. Several familiar plastic materials will be granulated with powder bentonite such as PVC, ABS and the material mixed with PP and PE, and so on. The granulation products are named as P-B adsorbent, A-B adsorbent and P-P-B adsorbent respectively. By some contrast experiments, the P-P-B adsorbent is selected to be activated by microwave and to treat the wastewater containing Cr3+, etc. because of its superior properties.The conclusions can be obtained as the following:(1) PVC, ABS and the mixed material all can be combined and granulated with the bentonite. And the granularity of the products can be controlled ranging between 2.5 and 5mm.(2) During the course of the oscillation in the water, it will not happen that the bentonite will be brushed off the adsorbent and the adsorbent will not pulverize. When the churning speed ranges from 200 to 500r/min, the pulverization of the granulation products will not change apparently.(3) On condition that the single screw extruder is used as the experiment facility, the maximal dosage of bentonite in P-B, A-B and P-P-B adsorbent is 15%, 35% and 65% respectively. To decrease the manufacture cost of the granulation adsorbent, the P-P-B adsorbent is selected as the appropriate experiment material.(4) These three adsorbents above-mentioned all have good adsorption properties. And the change of dosage of bentonite does not affect their adsorption properties obviously. Adding appropriate vesicant can improve the adsorption properties of P-P-B adsorbent.(5) The factors that influence the adsorption capability of the grain adsorbent as the following: time of microwave activation, dosage of adsorbent, pH, rotating speed of the oscillator and adsorption time, etc. The optimum time of microwave activation is 4 min in this experiment. The removal of Cr3+ is enhanced along with the increment of the adsorbent dosage and pH. The optimum removal efficiency of Cr3+ appears when the rotating speed is at240r/min. The adsorption reaches saturation rapidly. The removal of Cr3+ changes little along with the increment of the initial concentration of the wastewater at the invariable mass ratio of Chromium to the adsorbent and increment of the adsorption temperature.(6) In the low concentration scope of Cr3+, the adsorption behavior to Cr3+ of the adsorbent is fit with Langmuir equation like the bentonite. But in the high concentration scope of Cr3+, its adsorption curve deviates from Langmuir equation.