Chromium (VI) remediation in aqueous solution by waste products (peel and seed) of mango (Mangifera indica L.) cultivars

The surface group characteristics of mango cultivar peels and seeds were evaluated by infrared spectra, PZC, and functional group composition. The adsorption/reduction of chromium (VI) in aqueous solutions was investigated by varying pH, contact time, initial Cr(VI) concentration, and adsorbent amount. The results show that both peel and seed powders of the mango cultivars showed significant adsorption/reduction capacity for Cr(VI) and that the desorption process obeys pseudo-second-order kinetics. Optimal adsorption occurred at pH 1.0, using a Cr(VI) concentration of 100 mg/L. On average, at pH 1.0, and a concentration of 3 g/L, the maximum adsorption/reduction capacity of Cr(VI) was 83% (peels 76%, seeds 90%). Of the mango powders tested, the most efficient were Tommy seed (100%) and Coite peel (98%) followed by Coite seed (96%) and Tommy peel powders (95%). The adsorption/reduction of Cr(VI) was complete (100%) by the mango seed, in comparison to the peel powders (97%) after 180 min. The data indicates that mango waste products, such as seed and peel powders, are both excellent candidates for the remediation of Cr(VI) from aqueous systems and due to the higher concentration of gallates and galloyl glucosides, the mango seed powders should be the powders of choice for future remediation projects.

     

Mechanisms of chromium and arsenite adsorption by amino-functionalized SBA-15

The adsorption of Cr(VI) and As(III) by amino-functionalized SBA-15 (NH₂-SBA-15) from single and binary systems were investigated in this work. The effects of pH and temperature on the adsorption of NH₂-SBA-15 were studied. Adsorption kinetics, isotherm model, and thermodynamics were studied to analyze the experimental data. pH 2 was the optimum condition for the adsorption of Cr(VI) and pH 4 for As(III) adsorption. Increasing temperature had a positive effect on the removal of both Cr(VI) and As(III). The Freundlich isotherm model can depict the adsorption process best. The pseudo-second-order kinetic model fitted well with the kinetic data of Cr(VI) and As(III) in the single-component system. In the binary system, the adsorption of As(III) by NH₂-SBA-15 was slightly enhanced with the presence of Cr(VI); however, As(III) had no obvious effect on the removal of Cr(VI). Regeneration experiments indicated that 0.1 mol/L NaHCO₃ was an efficient desorbent for the recovery of Cr(VI) and As(III) from NH₂-SBA-15; the desorption rates for Cr(VI) and As(III) were 91.6 and 33.59 %, respectively. After five recycling cycles, the removal rates were 88 and 7 % for Cr(VI) and As(III) adsorption by NH₂-SBA-15, respectively.     

Cu(II) removal using green adsorbents: kinetic modeling and plant scale-up design

Cu(II) adsorption in continuous column using green adsorbents like peanut and almond shell was investigated. Fourier transform infrared (FTIR) spectroscopy, Brunaer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), and Point of Zero charge (pH_pzc) determination have been used for characterization of the adsorbents. Experiments were conducted at various operating conditions to calculate the adsorption capacity of the adsorbents. Adsorption studies signify that both the adsorbents have good adsorptive capacity for Cu(II) ion. Equilibrium of adsorption was described using Langmuir isotherm and the highest q_max value for both the adsorbent were obtained at an operating condition of 20 ml/min flow rate, 15 mg/L influent Cu(II) concentration, and 7 cm bed depth. Regeneration of both the adsorbents suggests that these adsorbents can be used several times for Cu(II) removal. Seven different kinetic models were tested among which the modified dose response model was fitted well for peanut shell and the Thomas model was fitted well for almond shell. These fitted models were further used for scale-up design. Regeneration studies show that peanut shell and almond shell are useful up to the fifth adsorption cycle. Application of these adsorbents with industrial effluent was also reported. This study reveals that peanut and almond shells can be used for Cu(II) removal for industrial wastewater.

     

Investigation of the removal mechanism of Cr(VI) in groundwater using activated carbon and cast iron combined system

Zero-valent iron (Fe⁰) has been widely used for Cr(VI) removal; however, the removal mechanisms of Cr(VI) from aqueous solution under complex hydrogeochemical conditions were poorly understood. In this research, the mixed materials containing cast iron and activated carbon were packed in columns for the treatment of aqueous Cr(VI)-Cr(III) in groundwater with high concentration of Ca²⁺, Mg²⁺, HCO₃ ⁻, NO₃ ⁻, and SO₄ ²⁻. We investigate the influences of those ions on Cr(VI) removal, especially emphasizing on the reaction mechanisms and associated precipitations which may lead to porosity loss by using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques. The results show that the precipitations accumulated on the material surface were (Fe/Cr) (oxy)hydroxide, mixed Fe(III)-Cr(III) (oxy)hydroxides, Fe₂O₃, CaCO₃, and MgCO₃. During these reactions, the Cr(VI) was reduced to Cr(III) coupled with the oxidated Fe⁰ to Fe(II) through the galvanic corrosion formed by the Fe⁰-C and/or the direct electron transfer between Fe⁰ and Cr(VI). In addition, Cr(VI) could be reduced by aqueous Fe(II), which dominated the whole removal efficiency. The primary aqueous Cr(III) was completely removed together with Cr(III) reduced from Cr(VI) even when Cr(VI) was detected in the effluent, which meant that the aqueous Cr(III) could occupy the adsorption sites. In general, the combined system was useful for the Cr(VI)-Cr(III) treatment based on galvanic corrosion, and the hardness ions had a negative effect on Cr(VI) removal by forming the carbonates which might promote the passivation of materials and decrease the removal capacity of the system.

     

Gamma irradiation-induced decomposition of sulfamethoxazole in aqueous solution: the influence of additives,biological inhibitory,and degradation mechanisms

Sulfamethoxazole (SMX) was decomposed by using gamma irradiation in the presence of different additives such as NO₃ ⁻, NO₂ ⁻, Cr(VI), 2-propanol, and tert-butanol. The results demonstrated that NO₃ ⁻, NO₂ ⁻, 2-propanol, and tert-butanol inhibited SMX radiolytic removal. However, there existed a synergetic effect for radiolytic removal of the mixture containing SMX and Cr(VI). At an absorbed dose of 150 Gy, the removal percentages of SMX and Cr(VI) in the mixture were 73.5 and 84.6%, respectively, which was higher than the removal percentages of 70.6 and 4.1% for the single component of SMX and Cr(VI). This provides us an insight into treating the combined pollution in micro-polluted water. The SMX radiolytic removal followed a pseudo first-order reaction kinetic model, and the rate constant ratios of ·OH, e_aq ⁻, and H· towards SMX radiolysis were 10.4:1:2.9. In addition, 24-h bio-inhibitory to the macroalgae of SMX solution during gamma irradiation reached the maximum of 0.85 at an adsorbed dose of 100 Gy, then gradually decreased with the increasing adsorbed dose. Based on LC-MS analysis and quantum chemical calculation, the degradation intermediates were determined and concluded that SMX radiolytic removal was mainly via ·OH radical attack and direct decomposition of SMX molecule by gamma ray.

     

Removal of Cr(VI) and humic acid by using TiO2 photocatalysis

The removal efficiencies of Cr(VI) and HA, using a TiO(2)-mediated photocatalytic process, were investigated with variations in the pH, TiO(2) dosage and Cr(VI)/HA ratio. During the photocatalytic reaction, the total removal of Cr(VI) occurred through adsorption onto TiO(2), as well as its reduction to Cr(III). However, oxidation and adsorption were identified as important removal processes for the treatment of HA. Due to the anionic type adsorption onto TiO(2) and its acid-catalyzed photocatalytic reduction, the removal of Cr(VI) decreased with increasing pH, while that of HA increased with increasing pH. The TiO(2) dosage was also an important parameter for the removal of Cr(VI). As the TiO(2) dosage was increased to 2.5 g l(-1), the removal of Cr(VI) was continuously enhanced, but decreased at dosages above 3 g l(-1) due to the increased blockage of the incident UV light used for the photocatalytic reaction. The removal of Cr(VI) was greatly enhanced when the system contained both HA and Cr(VI) compared to Cr(VI) alone. Also, the removal of HA was greatly enhanced when the system contained both HA and Cr(VI) compared to HA alone. The removal of Cr(VI) was continuously enhanced as the HA concentration gradually increased; however, no further increase was observed above 20 mg l(-1) HA due to the increased absorption of the UV light. This result supports that the photocatalytic reaction, with illuminated TiO(2), could be applied to more effectively treat wastewater containing both Cr(VI) and HA than that containing a single species only.     

The biological responses and metal phytoaccumulation of duckweed Spirodela polyrhiza to manganese and chromium

The phytoaccumulation ability of duckweed Spirodela polyrhiza on manganese (Mn) and chromium (Cr) was assessed by exposing the plant to various concentrations of single or dual metals (5–70 mg L^?1 Mn, 2–12 mg L^?1 Cr(VI)) under laboratory conditions. The results showed that S. polyrhiza can tolerate Mn at high concentrations of up to 70 mg L^?1, and its growth rate was barely affected by Mn. The effects of Cr on S. polyrhiza growth were dose-dependent, and the growth was completely inhibited in the presence of 12 mg L^?1 Cr. Analysis of metal content in the plant biomass revealed a high accumulation of Mn (up to 15.75 mg per g of duckweed dry weight). The Cr bioaccumulation (from below detection limit to 2.85 mg Cr (11.84 mg Cr₂O₇ ^2?) per g of duckweed dry weight) increased with cultivation time and metal concentration in the medium. Further study with the concurrence of Mn and Cr showed increased toxicity to plant growth and photosynthesis. The metal accumulations in the dual metal treatments were also significantly decreased as compared to the single metal treatments. Nevertheless, the phytoaccumulation of these two metals in S. polyrhiza in the dual metal treatments were still comparable to or higher than in previous reports. Thus, it was concluded that duckweed S. polyrhiza has the potential to be used as a phytoremediator in aquatic environments for Mn and Cr removal.

     

Preparation of a novel iron-based biochar composite for removal of hexavalent chromium in water

The chitosan-stabilized ferrous sulfide nanoparticles were loaded on biochar to prepare a composite material FeS-CS-BC for effective removal of hexavalent chromium in water. BC and FeS-CS-BC were characterized by Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses. Batch experiments were employed to evaluate the Cr(VI) removal performance. The experimental results showed that the removal rate of Cr(VI) by FeS-CS-BC(FeS:CS:BC?=?2:2:1) reached 98.34%, which was significantly higher than that of BC (44.58%) and FeS (79.91%). In the pH range of 2–10, the removal of Cr(VI) by FeS-CS-BC was almost independent of pH. The limitation of coexisting anions (Cl^?、SO₄^2?、NO₃^?) on Cr(VI) removal was not too obvious. The removal of Cr(VI) by FeS-CS-BC was fitted with the pseudo-second-order dynamics, which was a hybrid chemical-adsorption reaction. The X-ray photoelectron spectroscopy (XPS) analysis result showed that Cr(VI) was reduced, and the reduced Cr(VI) was fixed on the surface of the material in the form of Cr(VI)–Fe(III).

Removal of hexavalent chromium from wastewater by FeS-CS-BC composite synthesized by impregnation.

     

Selective removal of Cr(VI) from aqueous solution by adsorption on mangosteen peel

Mangosteen peel, rich in polyphenolic compounds, was used to prepare the adsorbent exhibiting highly selective adsorption for Cr(VI) over other metal ions such as Pb²⁺, Fe³⁺, Zn²⁺, Cd²⁺, and Cr³⁺ at the pH values of 1～4. The chemical modification method proposed by using calcium hydroxide is quite cost-effective and ecofriendly without using any toxic reagents or causing any secondary pollution. The adsorption isotherm results revealed that the adsorption of Cr(VI) on the gel fit well the Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) at pH levels 1, 2, 3, and 4 was evaluated to be 2.46, 2.44, 1.99, and 2.14 mol/kg, respectively. The adsorption mechanism for Cr(VI) on the saponified gel was verified to follow an esterifiaction reaction coupled with the reduction of Cr(VI) to Cr(III) in which H⁺ plays a role of promoter. Thus, modified mangosteen peel gel has the prominent selectivity and low cost for Cr(VI) removal.     

Cr(VI) sorption by free and immobilised chromate-reducing bacterial cells in PVA–alginate matrix: equilibrium isotherms and kinetic studies

Chromate-resistant bacterial strain isolated from the soil of tannery was studied for Cr(VI) bioaccumulation in free and immobilised cells to evaluate its applicability in chromium removal from aqueous solution. Based on the comparative analysis of the 16S rRNA gene, and phenotypic and biochemical characterization, this strain was identified as Paenibacillus xylanilyticus MR12. Mechanism of Cr adsorption was also ascertained by chemical modifications of the bacterial biomass followed by Fourier transform infrared spectroscopy analysis of the cell wall constituents. The equilibrium biosorption analysed using isotherms (Langmuir, Freundlich and Dubinin–Redushkevich) and kinetics models (pseudo-first-order, second-order and Weber–Morris) revealed that the Langmuir model best correlated to experimental data, and Weber–Morris equation well described Cr(VI) biosorption kinetics. Polyvinyl alcohol alginate immobilised cells had the highest Cr(VI) removal efficiency than that of free cells and could also be reused four times for Cr(VI) removal. Complete reduction of chromate in simulated effluent containing Cu²⁺, Mg²⁺, Mn²⁺ and Zn²⁺ by immobilised cells, demonstrated potential applications of a novel immobilised bacterial strain MR12, as a vital bioresource in Cr(VI) bioremediation technology.     

Comparative and competitive adsorption of Cr(VI), As(III), and Ni(II) onto coconut charcoal

This study evaluates the behavior of coconut charcoal (AC) to adsorb Cr(VI), As(III), and Ni(II) in mono- and multicomponent (binary and ternary) systems. Batch experiments were carried out for mono- and multicomponent systems with varying metal ion concentrations to investigate the competitive adsorption characteristics. The adsorption kinetics followed the mechanism of the pseudo-second-order equation in both single and binary systems, indicating chemical sorption as the rate-limiting step of adsorption mechanism. Equilibrium studies showed that the adsorption of Cr(VI), As(III), and Ni(II) followed the Langmuir model and maximum adsorption capacities were found to be 5.257, 0.042, and 1.748 mg/g, respectively. In multicomponent system, As(III) and Ni(II) adsorption competed intensely, while Cr(VI) adsorption was much less affected by competition than As(III) and Ni(II). With the presence of Cr(VI), the adsorption capacities of As(III) and Ni(II) on AC were higher than those in single system and the metal sorption followed the order of Ni(II)?>?As(III)?>?Cr(VI). The results from the sequential adsorption–desorption cycles showed that AC adsorbent held good desorption and reusability.     

Zero-valent iron and iron oxide-coated sand as a combination for removal of co-present chromate and arsenate from groundwater with humic acid

The combination of zero-valent iron (Fe⁰) and iron oxide-coated sand (IOCS) was used to remove Cr(VI) and As(V) from groundwater in this study. The efficiency and the removal mechanism of Cr(VI) and As(V) by using this combination, with the influence of humic acid (HA), were investigated using batch experiments. Results showed that, compared to using Fe⁰ or IOCS alone, the Fe⁰-IOCS can perform better on the removal of both Cr(VI) and As(V). Metal extraction studies showed that As(V) was mainly removed by IOCS and iron corrosion products while Cr(VI) was mainly removed by Fe⁰ and its corrosion products. Competition was found between Cr(VI) and As(V) for the adsorption sites on the iron corrosion products. HA had shown insignificant effects on Cr(VI) removal but some effects on As(V) removal kinetics. As(V) was adsorbed on IOCS at the earlier stage, but adsorbed/coprecipitated with the iron corrosion products at the later stage.     

Management of hazardous fly-ash energy waste in the adsorptive removal of diclofenac by the use of synthetic zeolitic materials

Zeolite-carbon composites (Na-P1(C), Na-X(C)) and pure zeolites (Na-P1, Na-X) were synthesized from hazardous high-carbon fly ash waste (HC FA) via hydrothermal reaction with sodium hydroxide (NaOH). These solids were applied in the removal of diclofenac (DCF) from aqueous solution, with and without poly(acrylic acid) (PAA). The experiments included adsorption–desorption measurements, as well as electrokinetic and stability analyses. The obtained results showed that HC FA and Na-P1(C) had the greatest adsorption capacity towards DCF, i.e., 26.51 and 21.19 mg/g, respectively. PAA caused considerable decrease in the DCF adsorption due to the competition of both adsorbates of anionic character for active sites. For example, the adsorbed amount of DCF on Na-P1 without PAA was 14.11 mg/g, whereas the one measured with PAA was 5.08 mg/g. Most of prepared solids were effectively regenerated by the use of NaOH. Desorption degree reached even 73.65% in the single systems (with one adsorbate) and 97.24% in the mixed ones (with two adsorbates). Zeolitic materials formed suspensions of rather low stability, which underwent further deterioration in the organic molecules presence. All the results obtained in this study indicated that HC FA can be successfully managed in the removal of organic substances.

     

Technical feasibility study of a low-cost hybrid PAC-UF system for wastewater reclamation and reuse: a focus on feedwater production for low-pressure boilers

This study has applied the concept of the hybrid PAC-UF process in the treatment of the final effluent of the palm oil industry for reuse as feedwater for low-pressure boilers. In a bench-scale set-up, a low-cost empty fruit bunch-based powdered activated carbon (PAC) was employed for upstream adsorption of biotreated palm oil mill effluent (BPOME) with the process conditions: 60 g/L dose of PAC, 68 min of mixing time and 200 rpm of mixing speed, to reduce the feedwater strength, alleviate probable fouling of the membranes and thus improve the process flux (productivity). Three polyethersulfone ultrafiltration membranes of molecular weight cut-off (MWCO) of 1, 5 and 10 kDa were investigated in a cross-flow filtration mode, and under constant transmembrane pressures of 40, 80, and 120 kPa. The permeate qualities of the hybrid processes were evaluated, and it was found that the integrated process with the 1 kDa MWCO UF membrane yielded the best water quality that falls within the US EPA reuse standard for boiler-feed and cooling water. It was also observed that the permeate quality is fit for extended reuse as process water in the cement, petroleum and coal industries. In addition, the hybrid system’s operation consumed 37.13 Wh m⁻³ of energy at the highest applied pressure of 120 kPa, which is far lesser than the typical energy requirement range (0.8–1.0 kWh m⁻³) for such wastewater reclamation.

     

Biosorption of Cr(VI) and Zn(II) ions from aqueous solution onto the solid biodiesel waste residue: mechanistic, kinetic and thermodynamic studies

In this present study, the biosorption of Cr(VI) and Zn(II) ions from synthetic aqueous solution on defatted J atropha oil cake (DJOC) was investigated. The effect of various process parameters such as the initial pH, adsorbent dosage, initial metal ion concentration and contact time has been studied in batch-stirred experiments. Maximum removal of Cr(VI) and Zn(II) ions in aqueous solution was observed at pH 2.0 and pH. 5.0, respectively. The removal efficiency of Cr(VI) and Zn(II) ions from the aqueous solution was found to be 72.56 and 79.81 %, respectively, for initial metal ion concentration of 500 mg/L at 6 g/L dosage concentration. The biosorbent was characterized by Fourier transform infrared, scanning electron microscopy and zero point charge. Equilibrium data were fitted to the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models and the best fit is found to be with the Freundlich isotherm for both Cr(VI) and Zn(II) metal ions. The kinetic data obtained at different metal ion concentration have been analysed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models and were found to follow the pseudo-second-order kinetic model. The values of mass transfer diffusion coefficients (D _e) were determined by Boyd model and compared with literature values. Various thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, were analysed using the equilibrium constant values (K _e) obtained from experimental data at different temperatures. The results showed that biosorption of Cr(VI) and Zn(II) ions onto the DJOC system is more spontaneous and exothermic in nature. The results indicate that DJOC was shown to be a promising adsorbent for the removal of Cr(VI) and Zn(II) ions from aqueous solution.     

Simultaneous reduction of Cr(VI) and oxidation of As(III) by Bacillus firmus TE7 isolated from tannery effluent

Hexavalent chromium [Cr(VI)] and arsenite [As(III)] are the most toxic forms of chromium and arsenic respectively, and reduction of Cr(VI) to Cr(III) and oxidation of As(III) to As(V) has great environmental implications as they affect toxicity and mobility of these toxic species. Bacillus firmus strain TE7, resistant to chromium and arsenic was isolated from tannery effluent. The strain exhibited ability to reduce Cr(VI) and oxidize As(III). It reduced 100 mg L^?1 Cr(VI) within 60 h in nutrient broth and oxidized 150 mg L^?1 As(III) within 10 h in minimal medium. It also completely reduced 15 mg L^?1 Cr(VI) and oxidized 50 mg L^?1 of As(III) simultaneously in minimal medium. To the best of our knowledge, this is the first bacterial strain showing simultaneous reduction of Cr(VI) and oxidation of As(III) and is a potential candidate for bioremediation of environments contaminated with these toxic metal species.     

Waste Fe(III)/Cr(III) hydroxide as adsorbent for the removal of Cr(VI) from aqueous solution and chromium plating industry wastewater

Fe(III)/Cr(III) hydroxide, a waste material from the fertilizer industry, has been used for the adsorption of Cr(VI) from aqueous solution, over a range of initial metal ion concentrations (5-30 mg litre(-1)), agitation times (1-180 min), adsorbent dosages (100-1200 mg per 50 ml), temperatures (24, 29 and 38 degrees C) and pH values (4.5-10). The adsorption of Cr(VI) increased with the initial concentration of Cr(VI) and with temperature. The process of uptake follows both the Langmuir and the Freundlich isotherm models. The applicability of Lagergren and empirical kinetic models has also been investigated. Almost quantitative removal of Cr(VI) at 10 mg litre(-1) in a 50-ml solution by 500 mg of adsorbent was found at an equilibrium pH of 5.6. The efficiency of chromium removal was also tested using wastewater from the chromium plating industry.     

Biosorption of chromium (VI) from aqueous solutions and ANN modelling

The use of sustainable, green and biodegradable natural wastes for Cr(VI) detoxification from the contaminated wastewater is considered as a challenging issue. The present research is aimed to assess the effectiveness of seven different natural biomaterials, such as jackfruit leaf, mango leaf, onion peel, garlic peel, bamboo leaf, acid treated rubber leaf and coconut shell powder, for Cr(VI) eradication from aqueous solution by biosorption process. Characterizations were conducted using SEM, BET and FTIR spectroscopy. The effects of operating parameters, viz., pH, initial Cr(VI) ion concentration, adsorbent dosages, contact time and temperature on metal removal efficiency, were studied. The biosorption mechanism was described by the pseudo-second-order model and Langmuir isotherm model. The biosorption process was exothermic, spontaneous and chemical (except garlic peel) in nature. The sequence of adsorption capacity was mango leaf > jackfruit leaf > acid treated rubber leaf > onion peel > bamboo leaf > garlic peel > coconut shell with maximum Langmuir adsorption capacity of 35.7 mg g^?1 for mango leaf. The treated effluent can be reused. Desorption study suggested effective reuse of the adsorbents up to three cycles, and safe disposal method of the used adsorbents suggested biodegradability and sustainability of the process by reapplication of the spent adsorbent and ultimately leading towards zero wastages. The performances of the adsorbents were verified with wastewater from electroplating industry. The scale-up study reported for industrial applications. ANN modelling using multilayer perception with gradient descent (GD) and Levenberg-Marquart (LM) algorithm had been successfully used for prediction of Cr(VI) removal efficiency. The study explores the undiscovered potential of the natural waste materials for sustainable existence of small and medium sector industries, especially in the third world countries by protecting the environment by eco-innovation.     

树脂吸附法处理氯霉素中间体DL-氨基物合成废水

研究了树脂吸附法处理氯霉素生产中产生的DL 1 对硝基苯基 2 氨基 1 ,3 丙二醇 (DL 氨基物 )碱解废水的工艺。结果表明 ,NG 1 0 0超高交联吸附树脂对废水中DL 氨基物具有较好的吸附性能。在试验条件下 ,废水CODCr为 72 0 0mg/L ,DL 氨基物含量为 2 86 5mg/L ,批处理 1 7BV时 ,平均出水CODCr降至 89 3mg/L ,CODCr去除率 >98% ;出水中DL 氨基物未检出 ,去除率近 1 0 0 %。树脂经稀酸脱附处理后 ,再生性能良好 ,高浓脱附液可直接回用于氯霉素生产酸性水解工艺中 ,使回收物得到有效利用