THEATMENT OF WASTEWATER FROM PRODUCTION PROCESS OF 2,3-ACID

Wastewater from production process of 2,3-acid was treated by adsorption usingmacroporous resin NDA-708. After only one-step treatment by resin adsorption, removalefficiency of three kinds of naphthalene chemicals was above 99%, removal efficiency ofCODcr was above 96% Under proper operating condition, desorption efficiency wasaround 100%. The running records of the industrial facility showed that the naphthlenechemicals in desorption effluent could be reused without obvious influence on the qualityOf the product.

TREATMENT AND RESOURSE REUSE OF INDUSTRIAL WASTEWATER FROM PRODUCTION PROCESS OF PHENYL ACETIC ACID

The effluent from phenyl acetic acid (PhCH2COOH) production process can betreated with NDA-999 macroporous polymeric adsorbent with about 100% removalefficiency of PhCH2COOK benzyl alcohol (PhCH2OH)and benzaldehyde (PhCHO) aswell as the decrease in Total Organic Carbon (TOC)from 4691mg/l to <300mg/L. 3. 7kgPhCH2COOH and 120kg NaCl will be recovered from per m3 wastewater and theadsorbent can be reused after being regenerated by NaOH aqueous solution andmethanol. Good economic, social and environmental results can be achieved with thismethod.

STUDY ON THE TREATMENT OF INDUSTRIAL WASTEWATER CONTAINING TRIETHYLAMINE WITH POLYMERIC ADSORBENTS

The treatment of the industrial wastewater, in which the concentration of triethylamine (TEN) and CODcr was around 3450 mg/L and 22400 mg/L respectively, was studied by adsorption of macroporous resins. Results demonstrate that the polymeric adsorbent CHA-111 has excellent effect on the adsorption and desorption of TEN. The concentration of TEN in the effluent is less than 30mg/L, and the removal efficiency of TEN and total CODcr exceed 99% and 95% respectively. The accumulation and resource reuse of TEN can be realized in this process.

SORPTION OF PHENOL AND P-NITROPHENOL ONTO A WEAKLY ANION EXCHANGER: XPS ANALYSIS AND MECHANISM

X-ray photoelectron spectroscopy(XPS)was adopted to elucidate sorption mechanism of phenol and p-nitrophenol onto a weakly anion exchanger D301.The distribution of specific forms of tertiary amino group on D301 was obtained and effect of free tertiary amino group on phenol sorption onto D301 was discussed. The result indicated that the percent of the protonated tertiary amine group on polymeric matrix was much lower than the reference compound N,N-dimethylbenzylamine at an identical pH value in solution due to the much lower activity degree of hydrogen ion in inner resin phase than in the external solution. Less free amino group on D301 results in less sorption capacity of phenol and p-nitrophenol in an acidic solution. Under the experimental conditions both phenol sorption onto D301 can be explained as solid extraction and the distribution coefficient varies linearly with the content of free amino group on D301.

Preparation of polymer-supported hydrated ferric oxide based on Donnan membrane effect and its application for arsenic removal

In the present study a novel technique was proposed to prepare a polymer-supported hydrated ferric oxide (D201-HFO) based on Donnan membrane effect by using a strongly basic anion exchanger D201 as the host material and FeCl3-HCl-NaCl solution as the reaction environment. D201-HFO was found to exhibit higher capacity for arsenic removal than a commercial sorbent Purolite ArsenX. Furthermore, it presents favorable adsorption selectivity for arsenic removal from aqueous solution, as well as satis- factory kinetics. Fixed-bed column experiments showed that arsenic sorption on D201-HFO could re- sult in concentration of this toxic metalloid element below 10 μg/L, which was the new maximum con- centration limit set recently by the European Commission and imposed by the US EPA and China. Also, the spent D201-HFO is amenable to efficient regeneration by NaOH-NaCl solution.

Recyclable polymer-based nano-hydrous manganese dioxide for highly efficient Tl(I) removal from water

Tl(I)in water even at a trace level is fatal to human beings and the ecosystem.Here we fabricated a new polymer-supported nanocomposite(HMO-001)for efficient Tl(I)removal by encapsulating nanosized hydrous manganese dioxide(HMO)within a polystyrene cation exchanger(D-001).The resultant HMO-001 exhibited more preferable removal of Tl(I)than D-001 and IRC-748,an iminodiacetic chelating polymer,particularly in the presence of competing Ca(II)ions at greater levels in solution.Such preference was ascribed to the Donnan membrane effect caused by D-001 as well as the specific interaction between Tl(I)and HMO.The adsorbed Tl(I)was partially oxidized into insoluble Tl(III)by HMO at acidic pH,while negligible oxidation was observed at circumneutral pH.The exhausted HMO-001 was amenable to efficient regeneration by binary NaOH-NaClO solution for at least 10-cycle batch runs without any significant capacity loss.Fixed-bed column test of Tl(I)-contained industrial effluent and natural water further validated that Tl(I)retention on HMO-001 resulted in a conspicuous concentration drop from 1.3 mg/L to a value lower than 0.14 mg/L(maximum concentration level for industrial effluent regulated by US EPA)and from 1–4?g/L to a value lower than 0.1?g/L(drinking water standard regulated by China Health Ministry),respectively.

Development of cation exchanger-based nano-CdS hybrid catalyst for visible-light photodegradation of rhodamine B from water

A new polymeric nanocomposite photocatalyst A15-CdS with large spherical beads (0.70-0.80 mm in diameter) was fabricated for efficient Rhodamine B (RhB) photodegradation with facile separation during cyclic runs,and photocorrosion,a congenital drawback of CdS,was successfully inhibited for A15-CdS.The nanocomposite catalyst was obtained by impregnating CdS nanoparticles within porous polymeric cation exchanger A15 through a facile inner-surface deposition.CdS nanoparticles (<20 nm) immobilized in A15 were deliberately distributed within an outside ring-like region of 40-50 m in depth,which is dominant for photoreaction because visible light is not expected to permeate through the inner region of nontransparent A15.As expected,efficient RhB photodegradation by A15-CdS was achieved under visible light irradiation,and large-size A15-CdS beads are expected to result in their facile separation from solution for repeated use.More significantly,negligible photocorrosion for the hybrid catalyst A15-CdS was demonstrated by the constant photodegradation efficiency and negligible CdS loss during five-cycle runs.The results indicated that nano-CdS immobilization within A15 would greatly improve the applicability of CdS nanoparticles in practical environmental remediation.