水处理用活性炭改性研究

研究了锆（Zr）和十六烷基三甲基氯化铵（CTAC）联合改性活性炭的制备，并考察Zr-CTAC改性活性炭对水中硝酸盐和磷酸盐的吸附作用及相关吸附机制，着重论述了锆（Zr）和十六烷基三甲基氯化铵联合改性活性炭（Zr-CTAC-AC）对水中硝酸盐和磷酸盐的吸附去除作用，结果表明Zr-CTAC-AC对水中硝酸盐和磷酸盐均具备较好的吸附去除能力。     

饮用水预处理去除备用水源三卤甲烷生成潜能

针对镇江金山湖备用水源,考察混凝、预氧化、预氯化、粉末活性炭吸附以及与预氧/氯化联用工艺对天然原水三卤甲烷生成潜能(THMFP)和UV254的去除效果。结果表明,3种无机盐混凝剂中三氯化铁去除效果最好,且去除效果随投加量增大而提高;高锰酸钾预氧化在低投加量时可取得良好效果,增大投加量去除率降低;次氯酸钠预氯化会产生大量THMs,不宜单独使用;粉末活性炭吸附去除效果分别随时间和投加量增加而增大;预氧/氯化与粉末活性炭联用工艺去除率最高(60%),且活性炭吸附可大大减少预氯化产生的THMs。     

活性炭吸附法去除印染工业废水色度的试验与研究

通过试验初步研究活性炭直接吸附去除印染工业废水色度中吸附剂投加量、吸附时间等对色度去除率的影响。通过混凝沉淀法与活性炭吸附法结合、搅拌电解法与活性炭吸附法结合、脱色氧化法与活性炭吸附法结合等试验初步探讨了活性炭吸附与其它处理方法结合去除印染工业废水色度的可行性。同时，讨论了以上几种处理方法对水样中CODCr的去除、水样pH值变化等的影响。     

改性凹凸棒土复配PAC去除水源水中突发性重金属铜污染研究

以聚合氯化铝为絮凝剂采用强化混凝的处理方法,对水源水中突发性重金属铜的去除进行研究,考察混凝剂投加量和投加改性凹凸棒土等对Cu2+去除率的影响。结果表明,常规工艺对铜的最大去除率为67%,加入改性凹凸棒土可显著提高混凝效果,组合工艺去除铜的最优条件是,聚合氯化铝投加量为30mg/L,改性凹凸棒土投加量为30mg/L,在混凝前1min投加,此时铜的去除率达85%以上。     

利用改性凹凸棒石处理含油工业废水

利用改性后的凹凸棒石颗粒吸附剂进行含油工业废水处理实验。取样处理实验结果表明,改性粘土颗粒吸附剂的吸附量远大于活性炭,且处理效果好。在废水含油浓度72mg/L时,吸附剂可处理废水1.18m3/kg,停留时间约8min。用加热法对吸附饱和后的凹凸棒石颗粒可进行5次再生使用,且对油的吸附效率没有明显下降。清水淋沥实验表明,制备的改性凹凸棒石颗粒有很好的持油性,油释放率仅为2.05%。     

炼油废水回用于循环冷却水系统深度处理技术

为解决水资源紧缺问题,提高工业水资源的利用率,减少污水排放,采用臭氧催化氧化—活性炭吸附—石灰软化的工艺组合,深度处理炼油厂中二级处理达标排放的污水,探讨最佳工艺参数的选择,进行二级出水回用于循环冷却水的试验研究。试验表明:在臭氧氧化接触时间为40min,活性炭柱吸附通水流量为2L/h,石灰乳投加量0.32g/L、碳酸钠溶液0.06～0.10g/L、石灰软化搅拌15～20min,能使整套工艺达到最佳处理效果。小试阶段COD、氨氮、总硬度及总碱度的去除率分别达到96.00%、44.49%、64.61%、67.85%,硫酸根和氯离子均有所下降,通过整套工艺深度处理后,所得中水可作为循环冷却系统补充水。     

电化学氧化处理特殊点源含油污水实验

文章采用电化学氧化法对特殊点源含油污水进行预处理,实验考察了电解时间、电极结构、电流密度对污染物去除效果的影响以及可生化性的改善情况,探究了电解过程中余氯、总氯变化情况,并对比了静置与活性炭吸附对余氯和总氯的去除情况。实验结果表明,以Ti/RuO_2-IrO_2板状电极为阳极、金属Ti板为阴极,当实验条件为电流密度80 A/m~2、电解120 min时,氨氮去除率达95.5%,COD去除率达56.7%,B/C值由0.19提高到0.33,此时对应的能耗为8.36 (kW·h)/m~3;电解出水经活性炭吸附180 min后,余氯浓度降至0.97 mg/L,总氯浓度降至3.72 mg/L。     

焙烧水滑石去除水中硝酸盐的实验研究

利用层状双氢氧化物的结构记忆效应,探讨了焙烧水滑石处理模拟含硝酸盐废水的可行性,考察了pH值、温度、反应时间、振荡速度等因素对硝酸盐去除率的影响。结果表明,当pH为9、反应温度298K、吸附时间120min、LDO投加量0.1g/100ml时,硝酸盐氮初始浓度为100mg/L;震荡速度为150r/min时,总氮的去除率高达96.73%。焙烧水滑石对硝酸盐的吸附符合Freudlich等温方程。     

城市剩余污泥制备吸附剂的研究及其应用

以城市污水处理厂的剩余污泥为原料,采用化学活化法制备活性碳污泥吸附剂.通过对比不同活化剂活化效果,并对影响活化产物吸附性能的因素进行了研究.结果表明以3mol/L的ZnCl2为活化剂,活化温度为550℃,固液比为1:2.5,热解时间2h,制备的活性碳吸附剂吸附碘值为317.4mg/g,活性炭吸附剂比表面积为232.526m2/g.采用制备的活性碳吸附剂处理模拟废水COD去除效果较好.     

邻甲苯酚生产含酚废水处理试验

采用活性炭吸附和过氧化氢氧化两步联合处理邻甲苯酚生产含酚废水。通过试验得到活性炭吸附等温方程，活性炭去除COD负荷为550（mg/g－活性炭）；氧化处理的最佳配比，以及过氧化氢投加量等处理工艺条件。在试验选定的最佳条件下处理废水，挥发酚的去除率达100％，CODcr去除率达95％。     

Removal of chromium (VI) from aqueous solution using walnut hull

In this study, removal of chromium (VI) from aqueous solution by walnut hull (a local low-cost adsorbent) was studied. The extent of adsorption was investigated as a function of solution pH, contact time, adsorbent and adsorbate concentration, reaction temperature and supporting electrolyte (sodium chloride). The Cr (VI) removal was pH-dependent, reaching a maximum (97.3%) at pH 1.0. The kinetic experimental data were fitted to the first-order, modified Freundlich, intraparticle diffusion and Elovich models and the corresponding parameters were obtained. A 102.78 kJ/mol Ea (activation energy) for the reaction of chromium (VI) adsorption onto walnut indicated that the rate-limiting step in this case might be a chemically controlled process. Both the Langmuir and Freundlich isotherms were suitable for describing the biosorption of chromium (VI) onto walnut hull. The uptake of chromium (VI) per weight of adsorbent increased with increasing initial chromium (VI) concentration up to 240-480 mg/L, and decreased sharply with increasing adsorbent concentration ranging from 1.0 to 5.0 g/L. An increase in sodium chloride (as supporting electrolyte) concentration was found to induce a negative effect while an increase in temperature was found to give rise to a positive effect on the chromium (VI) adsorption process. Compared to the various other adsorbents reported in the literature, the walnut hull in this study shows very good promise for practical applicability.     

Phenol removal from aqueous environments by natural & chemically modified kaolin clay

Natural, acid and base modified kaolin clays were studied for the sake of phenol and 4-chlorophenol removal from aqueous environments and their application to real ground and industrial wastewater samples. Scanning electron microscope (SEM), infrared spectroscopy (IR), X-ray diffraction (XRD), Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA), and Surface area analysis were employed for characterization of the adsorbents microstructure. Operating factors such as adsorbent dose, solution pH, initial phenol concentration, and contact time were studied. The experimental data displayed that the increase of the adsorbent dose, contact time, and pH value from 2 to 7 increases the efficiency of the removal process. Optimal conditions for phenolic removal were; contact time of 300 min, primary phenol solution of 25 mg/L, pH 7 and 2.5 g/L as an appropriate adsorbent dose using crude (natural), acid modified and base modified kaolin clays. The higher phenolic removal efficiencies were obtained at 5 mg/L as 90, 97, 96.2%, respectively, for the adsorbents in the previously mentioned order. The adsorption capacity in the removal of phenol and 4-chlorophenol were 7.481 and 4.195, 8.2942 and 3.211, and 8.05185 and 18.565 mg/g, respectively, for the adsorbents in the same mentioned order. The adsorption equilibrium data were fitted and analyzed with four isotherm models, namely, Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm equations. The adsorption process of phenol on studied adsorbents was exothermic, spontaneous and thermodynamically favorable proved by the negative values of their thermodynamic parameters ΔH° and ΔG°. The correlation coefficient (R²) for all concentrations was higher than 0.94, which indicates that in the studied system, the data suitably fit the first-order kinetics. The % desorption capacity was amounted to 96%, 91.11%, and 87.06% of adsorbed phenol, respectively, for the adsorbents in the previous order using 0.1N NaOH and 10% V/V ethanol solutions as eluents at 25°C, indicating the reusability of the adsorbents. Kaolin and its modified forms can be introduced as eco-friendly and low-cost adsorbents in water remediation implementation.     

Exploitation of Trichoderma harzianum mycelial waste for the removal of rhodamine 6G from aqueous solution

The harvested mycelial waste of Trichoderma harzianum was used as an adsorbent for the removal of rhodamine 6G and was studied in batch mode. The effects of agitation time and initial dye concentration, adsorbent dosage and pH were examined. The study revealed that the amount of dye adsorbed (mgg(-1)) increased with increase in agitation time and reached equilibrium after 120 min, for dye concentrations of 10-50 mg L(-1). The adsorbent dosage of 1.0 g/50 mL and pH of 8.0 were found to be optimum for maximum dye removal. The batch mode adsorption data followed both the Langmuir and Freundlich isotherms. The pseudo first- and second-order rate kinetics were applied to the adsorbent system. The adsorption kinetics of rhodamine 6G showed that the pseudo-second-order kinetic model provided the best correlation of the equilibrium data. The study implies that it is possible to develop a dye removal system by using T. harzianum biomass, which occurs as sludge in waste stream of fermentation industries.     

篦齿眼子菜对废水中氮和磷的去除行为研究

一些常见的沉水草本植物对水质具有较强的净化作用,能够有效控制氮和磷的浓度。本试验通过模拟氮、磷污染的水质条件,采用篦齿眼子菜对氮、磷营养盐的吸附和去除效果进行研究。结果表明:设定模拟废水中的初始总氮(TN)浓度在1~50 mg/L范围内,培养30天后的植株对总氮的去除率最高可达85.4%,随着初始培养环境中总氮浓度的增加,去除效率呈下降的趋势;模拟废水水体中的总磷浓度范围为0.2~10.0 mg/L时,对总磷(TP)去除效率最高为78.3%。使用蓖齿眼子菜对实际的废水进行氮、磷营养盐的去除处理,效果较好。由此可见,水生植物富集废水中高浓度营养盐的能力具有较大的应用前景,本研究可为蓖齿眼子菜应用于废水预处理工艺提供可靠的理论支持。     

Removal of Fe(II) from the wastewater of a galvanized pipe manufacturing industry by adsorption onto bentonite clay

Bentonite clay has been used for the adsorption of Fe(II) from aqueous solutions over a concentration range of 80-200 mg/l, shaking time of 1-60 min, adsorbent dosage from 0.02 to 2 g and pH of 3. The process of uptake follows both the Langmuir and Freundlich isotherm models and also the first-order kinetics. The maximum removal (>98%) was observed at pH of 3 with initial concentration of 100 mg/l and 0.5 g of bentonite. The efficiency of Fe(II) removal was also tested using wastewater from a galvanized pipe manufacturing industry. More than 90% of Fe(II) can be effectively removed from the wastewater by using 2.0 g of the bentonite. The effect of cations (i.e. zinc, manganese, lead, cadmium, nickel, cobalt, chromium and copper) on the removal of Fe(II) was studied in the concentration range of 10-500 mg/l. All the added cations reduced the adsorption of Fe(II) at high concentrations except Zn. Column studies have also been carried out using a certain concentration of wastewater. More than 99% recovery has been achieved by using 5 g of the bentonite with 3M nitric acid solution.     

Physicochemical characterization of hydroxyapatite and its application towards removal of nitrate from water

A laboratory study was conducted to investigate the efficiency of hydroxyapatite (HAP) towards removal of nitrate from synthetic nitrate solution. In the present research HAP synthesized from egg-shell was characterized using SEM, XRD, FTIR and TGA–DSC. The removal of nitrate was 96% under neutral conditions, using 0.3 g of adsorbent in 100 mL of nitrate solution having an initial concentration of 100 mg/L. An adsorption kinetic study revealed that the adsorption process followed first order kinetics. Adsorption data were fitted to a linearly transformed Langmuir isotherm with correlation coefficient (R²) > 0.98. Thermodynamic parameters were also calculated to study the effect of temperature on the removal process. In order to understand the adsorption type, equilibrium data were tested with the Dubinin–Radushkevich isotherm. The process was rapid and equilibrium was established within the first 40 min.     

Adsorption of methylene blue from aqueous solution by jackfruit (Artocarpus heteropyllus) leaf powder: A fixed-bed column study

Continuous fixed-bed studies were undertaken to evaluate the efficiency of jackfruit leaf powder (JLP) as an adsorbent for the removal of methylene blue (MB) from aqueous solution under the effect of various process parameters like bed depth (5–10 cm), flow rate (30–50 mL/min) and initial MB concentrations (100–300 mg/L). The pH at point of zero charge (pH_PZC) of the adsorbent was determined by the titration method and a value of 3.9 was obtained. A FTIR of the adsorbent was done before and after the adsorption to find the potential adsorption sites for interaction with methylene blue molecules. The results showed that the total adsorbed quantities and equilibrium uptake decreased with increasing flow rate and increased with increasing initial MB concentration. The longest breakthrough time and maximum MB adsorption were obtained at pH 10. The results showed that the column performed well at low flow rate. Also, breakthrough time and exhaustion time increased with increasing bed depth. The bed-depth service time (BDST) model and the Thomas model were applied to the adsorption of MB at different bed depths, flow rates, influent concentrations and pH to predict the breakthrough curves and to determine the characteristic parameters of the column that are useful for process design. The two model predictions were in very good agreement with the experimental results at all the process parameters studied indicating that they were very suitable for JLP column design.     

Factors controlling phosphate interaction with iron oxides

Factors such as pH, solution ion composition, and the presence of natural organic matter (NOM) play a crucial role in the effectiveness of phosphorous adsorption by iron oxides. The interplay between these factors shows a complicated pattern and can sometimes lead to controversial results. With the help of mechanistic modeling and adsorption experiments, the net macroscopic effect of single and combined factors can be better understood and predicted. In the present work, the relative importance of the above-mentioned factors in the adsorption of phosphate was analyzed using modeling and comparison between the model prediction and experimental data. The results show that, under normal soil conditions, pH, concentration of Ca, and the presence of NOM are the most important factors that control adsorption of phosphate to iron oxides. The presence of Ca not only enhances the amount of phosphate adsorbed but also changes the pH dependency of the adsorption. An increase of dissolved organic carbon from 0.5 to 50 mg L can lead to a >50% decrease in the amount of phosphate adsorbed. Silicic acid may decrease phosphate adsorption, but this effect is only important at a very low phosphate concentration, in particular at high pH.     

改性玉米秸秆吸附去除废水中四环素的研究

应用平衡吸附法，研究了不同投加量（改性玉米秸秆）、温度及pH条件下，改性玉米秸秆对水体中四环素的吸附作用，并利用等温曲线及吸附动力学方程对试验结果进行了拟合。结果表明：在吸附剂用量0．4g，温度30℃，振荡时间30min，pH值7的条件下，对水体中四环素浓度为50．136mg／L的吸附率可达93．4％。四环素废水吸附均符合Langmuir及Freundlich等温模式。但Langmuir方程拟合得较好，Elovich方程能更好地拟舍改性玉米秸秆对水体中四环素的吸附动力学曲线。     

Adsorption of pharmaceuticals to microporous activated carbon treated with potassium hydroxide, carbon dioxide, and steam

Adsorption of sulfapyridine, tetracycline, and tylosin to a commercial microporous activated carbon (AC) and its potassium hydroxide (KOH)-, CO-, and steam-treated counterparts (prepared by heating at 850°C) was studied to explore efficient adsorbents for the removal of selected pharmaceuticals from water. Phenol and nitrobenzene were included as additional adsorbates, and nonporous graphite was included as a model adsorbent. The activation treatments markedly increased the specific surface area and enlarged the pore sizes of the mesopores of AC (with the strongest effects shown on the KOH-treated AC). Adsorption of large-size tetracycline and tylosin was greatly enhanced, especially for the KOH-treated AC (more than one order of magnitude), probably due to the alleviated size-exclusion effect. However, the treatments had little effect on adsorption of low-size phenol and nitrobenzene due to the predominance of micropore-filling effect in adsorption and the nearly unaffected content of small micropores causative to such effect. These hypothesized mechanisms on pore-size dependent adsorption were further tested by comparing surface area-normalized adsorption data and adsorbent pore size distributions with and without the presence of adsorbed antibiotics. The findings indicate that efficient adsorption of bulky pharmaceuticals to AC can be achieved by enlarging the adsorbent pore size through suitable activation treatments.