卤水-氨法碱式氯化镁晶须的制备及影响因素的研究

在常压下用液相反应法制备了碱式氯化镁晶须,研究了氯化镁浓度、氯化镁与氨水的摩尔比、反应温度、陈化温度、陈化时间对碱式氯化镁晶须制备的影响.根据XRD和SEM测试结果,提出了制备碱式氯化镁晶须的最佳工艺条件:(1)氯化镁浓度为3mol/l;(2)氯化镁与氨水的摩尔比为4:1～6:1;(3)最佳反应温度为30℃;(4)氨水的加料速度为10ml/min～20ml/min;(5)最佳陈化温度为50℃～60℃,最佳陈化时间为48h～72h.制备得到了长径比≥100碱式氯化镁晶须.     

影响魔芋葡甘聚糖吸附香兰素的因素研究

为探讨魔芋葡甘聚糖吸附香兰素的基本特征,以魔芋葡甘聚糖溶液浓度、pH值、温度和时间为试验因素,进行单因素试验,对结果进行方差分析。结果表明,随着魔芋葡甘聚糖浓度增大,香兰素吸附量呈增大趋势;随pH值升高,吸附量增加;温度越高,吸附量越低;随时间的延长,吸附量逐渐减少;魔芋葡甘聚糖吸附香兰素的工艺条件为：合适的魔芋葡甘聚糖与香兰素配比,魔芋葡甘聚糖溶液pH=9．0-11．0,常温下吸附,吸附时间10min。     

酿酒废弃葡萄皮渣对Cr(VI)的吸附能力研究

利用酿酒后废弃葡萄皮渣(WGP)作为吸附剂,对溶液中六价铬离子Cr(Ⅵ)进行吸附试验,研究了吸附时间、粒径、用量、溶液pH、Cr离子浓度对吸附率的影响。结果如下:WGP对Cr(Ⅵ)的吸附4 h就基本达到平衡,吸附率为87.97%;粒径小于60目的WGP表现出更强的吸附能力;吸附率与WGP用量正相关,用量1 g以上吸附率趋于稳定在88%左右;WGP对Cr(VI)的吸附率随着pH值增加而下降,直至pH为3时,吸附率趋于平衡;溶液中Cr浓度越高,葡萄皮渣对Cr(Ⅵ)的吸附率越高。研究表明:酿酒后葡萄皮渣具有较强吸附铬Cr(Ⅵ)的能力,可作为铬吸附剂,用于废水治理。     

化学修饰甘薯渣对碱性品红的吸附特性

以废弃甘薯渣为原料,经化学修饰处理得到了改性甘薯废渣生物吸附剂,并将用于对水溶液中印染物质碱性品红的吸附。针对改性甘薯渣加入量、粒径、碱性品红溶液初始浓度、溶液pH、吸附温度、吸附时间各因素对吸附率的影响进行实验,对影响显著的碱性品红初始浓度、改性甘薯渣加入量、吸附时间采用二次正交旋转组合设计优化,得碱性品红初始浓度200mg/L、改性甘薯渣加入量0.8 g、吸附时间140 min时模拟预测最大吸附率97.66%,同条件下实测97.38%,二者吻合。吸附平衡试验表明甘薯渣吸附剂对碱性品红吸附符合Langmuir和Frundlich模型,其最大吸附量为37.17mg/g。吸附动力学可用准二级动力学方程描述。BET及SEM表征分析可知改性甘薯渣优化后表面疏松多孔,且褶皱增多,有利于吸附过程进行。经FT-IR与EDS得知,羟基(-OH)、羧基(-COOH)在吸附过程中起到主要作用。     

改性香芋皮粉末对Cr(Ⅵ)的吸附性能

采用硫酸(1+19)溶液对香芋皮粉末进行改性制备吸附剂,利用静态吸附法,研究吸附剂粒径、投加量、吸附温度、吸附时间和初始废水的p H、Cr(Ⅵ)初始质量浓度对Cr(Ⅵ)吸附效果的影响。结果表明,吸附剂吸附Cr(Ⅵ)的最佳工艺条件为:改性香芋皮粉末的粒径200目,投加量1.0 g、吸附温度30℃、吸附时间360 min,初始废水p H 3以及Cr(Ⅵ)初始质量浓度150 mg/L。在此工艺条件下,改性香芋皮粉末吸附剂对Cr(Ⅵ)具有良好的吸附性能,对Cr(Ⅵ)的吸附量可达到7.491 mg/g,Cr(Ⅵ)的吸附率可达99.88%。用HCl溶液(1+5)对吸附饱和的吸附剂可解吸再生。     

活性炭吸附对苹果汁色值的影响

为了提高苹果汁的色值,采用活性炭吸附.分别考察了活性炭目数,活性炭添加量,吸附温度对色值的影响.得出最佳的吸附目数和添加量组合是:80目,添加量为0.015g/mL.吸附温度对果汁色值的影响是温度越高,果汁色值越低.     

莴笋叶渣吸附Cu2+研究

采用二次回归正交旋转组合设计方法对莴笋叶渣吸附Cu2+条件进行优化,建立加入量(X1)、质量浓度(X2)、时间(X3)、pH值(X4)、温度(X5)5个因素与吸附率(Y)的回归模型为:Y=85.45862+11.80098X1-6.85546X2+0.24918X3+2.14203X4+1.12124X5-4.75315X12-2.40953X22-2.23141X32-1.49228X42-3.40533X52+3.84570X1X2+0.61717X1X3-3.15888X1X4-0.26948X1X5-0.29760X2X3+0.77899X2X4-0.01867X2X5-0.23965X3X4-1.45840X3X5+0.94533X4X5。各因素对莴笋叶渣吸附Cu2+影响顺序为:加入量>质量浓度>pH值>温度>时间,在加入量0.9g、Cu2+质量浓度30mg/L、时间5h、pH3、温度40℃条件下,莴笋叶渣对Cu2+吸附率最高可达98.40%。验证值为97.96%,与理论值基本一致。对于60mg/L Pb2+溶液,莴笋叶渣为吸附剂时的最佳固液比为12g/L;莴笋叶渣对中低质量浓度Pb2+溶液的吸附效果好于活性炭。     

软锰矿脱硫尾渣对刚果红的吸附性能

研究软锰矿脱硫尾渣(PDS)对刚果红的吸附性能。用软锰矿脱硫尾渣对刚果红模拟染料废水进行吸附实验,研究了PDS投加量、吸附时间、染料初始质量浓度和温度对吸附效果的影响。对于初始质量浓度为100 mg/L的刚果红溶液,尾渣的最佳投加量为2.4 g/L,去除率达98%;尾渣对刚果红的吸附在前5 min达到60%~70%,并在360 min后达到平衡;随着染料初始质量浓度的增大,单位吸附量上升,但去除率有所下降;温度升高有利于吸附。吸附过程符合伪二级动力学模型,红外光谱分析说明尾渣对刚果红存在化学吸附作用。     

PEG-1000对多级孔ZSM-5分子筛合成及吸附性能的影响

以饱和ATP吸附材料为硅源,用四丙基溴化铵(TPABr)为微孔模板剂和聚乙二醇1000(PEG-1000)为介孔模板剂合成多级孔ZSM-5分子筛.通过X射线衍射分析(XRD)、傅里叶红外分析(FT-IR)、扫描电子显微镜(SEM)和比表面积及孔径分析仪等表征合成产物的形貌、结构及孔道特征;再利用亚甲基蓝溶液测试其吸附性能.结果表明PEG-1000投加量对合成产物的晶型影响不明显,皆为多级孔ZSM-5分子筛,均具有较大的比表面积(约300m~2/g).随着PEG-1000投加量提高,分子筛晶体逐渐粗糙并呈近球状,介孔量和平均孔径均有所增加;当PEG-1000投加量为0.30g时,比表面积为274.230 2m~2/g,介孔所占比例47.92%,平均孔径2.68nm.在亚甲蓝溶液质量浓度为10mg/L,pH为11,吸附150min时,所合成ZSM-5分子筛对亚甲基蓝吸附率达98.2%.     

胡萝卜渣对Cu~(2+)的吸附作用及吸附机理

通过静置吸附试验,研究了胡萝卜渣对铜离子吸附效果的影响因素及有关吸附机理。结果显示:吸附率随胡萝卜渣粒径的减小而增大,100目时胡萝卜渣对铜离子的吸附率可达76.35%;铜离子溶液初始浓度相同时,吸附率随胡萝卜渣加入量的增加而增大,而胡萝卜渣加入量相同时,对不同浓度的铜离子溶液吸附率均出现一次最小值;在铜离子的初始浓度为10mg/L和胡萝卜渣用量为0.5g时,对pH值、温度和浸泡时间3种因素,在6水平上进行了正交试验,最佳吸附条件为废水的pH值为2、温度为40℃、浸泡的时间为3h;20℃和40℃时铜离子的吸附等温线结果表明,胡萝卜渣对铜离子的吸附以单分子层吸附占优势,吸附等温线较好地符合Freundlich吸附等温式;铜离子的吸附动力曲线结果表明,胡萝卜渣对铜离子的吸附动力学行为比较符合二级动力学模型。     

HZSM-5/Y复合分子筛的制备、表征及催化裂化性能研究

以商用HZSM-5分子筛为母体,采用NaOH溶液对其进行预处理,在添加铝源和Y导向剂的作用下合成了HZSM-5/Y复合分子筛,并对其进行XRD、SEM和BET表征。考察了NaOH溶液浓度对复合分子筛结构和形貌的影响。进一步考察了该复合分子筛催化剂在油酸裂化反应中的催化特性,并与商用HZSM-5分子筛的催化特性作了比对。结果表明:当NaOH溶液浓度为1. 5mol/L时制备的HZSM-5/Y复合分子筛具有良好的分子筛结构,并且在催化裂化反应中表现出良好的性能。当使用该分子筛时,在反应温度475℃、质量空速6. 99 h-1条件下,液体产物产率达到了54. 2%,油酸脱氧率为38. 5%,液体产物酸价(KOH)为2. 6 mg/g;与使用商用HZSM-5分子筛相比,该复合分子筛对5~12个碳原子的链烃类的选择性更高,其裂化液体产物酸价更低,但重复使用效果较差。     

折光法快速测定豆腐制品生产用氯化镁溶液的浓度

利用折射率（通过糖度计测得的糖度表示）反映已知浓度的食用氯化镁溶液的浓度,绘制质量分数一折射率（糖度）标准曲线,利用标准曲线和折射率测定未知浓度的食用氯化镁溶液的的浓度,经误差计算确定能够满足豆腐制品生产需要的溶液浓度。     

Retention of ascorbic acid in pickles — effect of different spices and salt (an in vitro study)

Effect of spices, different concentration of sodium chloride and other salts on retention of ascorbic acid during storage period (21 days in case of spices and eight days for salts) was studied. The retention of ascorbic acid with the addition of 24% NaCl was 55%, followed by 37% with red chillies, fenugreek, turmeric; 32% with the addition of pepper, sugar and 26% with mustard and asafoetida. When all the spices and salt were added together, the retention was much higher (73%) than those with individual spices. Sodium chloride over a wide range of concentrations was found to have higher retention of ascorbic acid. The retention being 80%, when stored with 24.0% sodium chloride solution for eight days. Sulfates of sodium, potassium, magnesium and manganese or chlorides of magnesium or manganese did not have a significant effect on the retention of ascorbic acid. The retention with potassium chloride was close to that observed with sodium chloride.     

氧化镁铵盐法制备高纯过氧化镁

在氯化铵溶液体系中,以氧化镁,过氧化氢为原料,制备高纯过氧化镁。研究表明采用氧化镁活性大于100,氯化铵/氧化镁不小于10%,过氧化氢∶氧化镁不小于4∶1,反应温度大于40℃情况下,反应时间不小于30 min,可制备出纯度大于90%的过氧化镁。     

Pyrene and phenanthrene sorption to model and natural geosorbents in single- and binary-solute systems

Sorption of pyrene and phenanthrene to model (illite and charcoal) and natural (Yangtze sediment) geosorbents were investigated by batch techniques using fluorescence spectroscopy. A higher adsorption of phenanthrene was observed with all sorbents, which is related to the better accessibility of smaller molecules to micropores in the molecular sieve sorbents. In addition, pyrene sorption in binary-solute systems with a constant initial concentration of phenanthrene (0.1 μmol L(-1) or 2 μmol L(-1)) was studied. A 0.1 μmol L(-1) concentration of phenanthrene causes no competitive effect on the pyrene sorption. A 2 μmol L(-1) concentration of phenanthrene significantly suppresses the sorption of pyrene, especially in the low concentration range; nonlinearity of the pyrene sorption isotherms thus decreases. The competitive effect of 2 μmol L(-1) phenanthrene on the pyrene sorption is overestimated by the ideal adsorbed solution theory (IAST) using the fitted single sorption results of both solutes. An adjustment of the IAST application by taking into account the molecular sieve effect is proposed, which notably improves the IAST prediction for the competitive effect.     

SALT SUBSTITUTES IN CANNED LUNCHEON MEAT

Potassium chloride, magnesium chloride, calcium chloride and magnesium sulfate were used to replace 50% of the ionic strength of the sodium chloride in a luncheon meat product. The magnesium chloride treatment had a higher cook yield while all four treatments resulted in lower (P ≥ 0.05) thiobarbituric acid (TBA) values than the control. Samples from the calcium chloride and magnesium chloride treatments were lighter (P ≥ 0.05) in color than the control, suggesting that these two adjuncts were detrimental to product color. Total lipid content of the magnesium chloride treatment, which had a correspondingly higher cook yield, was greater (P > 0.05) than the other treatments. Cholesterol content of the magnesium chloride, calcium chloride, and magnesium sulfate treatments was higher (P ≥ 0.05) than the control. These results suggest that potassium chloride is a viable replacement for up to 50% of the ionic strength of sodium chloride in luncheon meat without any deleterious effects on product quality.     

均匀沉淀法制备纳米碱式碳酸镁粉体的研究

以MgC12·6H2O和CO(NH2)2为原料,采用均匀沉淀法合成纳米碱式碳酸镁.考察了反应温度、MgC12·6H2O浓度、反应物配比(CO(NH2)2:MgC12·6H2O)、反应时间等反应条件对碱式碳酸镁平均粒径的影响,确定了最佳工艺条件.通过透射电镜、X射线衍射仪对碱式碳酸镁进行表征和分析.结果表明:所得纳米碱式碳酸镁粒度分布均匀,平均粒径40 nm,粒子形状为球形.     

腐竹生产颜色加深的成因及护色方法初探

腐竹在制作过程中颜色随着加热时间的延长而逐渐加深。通过测定腐竹制作过程中豆浆蛋白质、脂肪、还原糖浓度的变化,对腐竹色泽变化的机理进行初步分析,从而找到腐竹护色的有效方法。结果表明,随着加热时间的延长和揭皮次数的增加,豆浆中蛋白质、脂肪、还原糖浓度上升;氯化钙、氯化镁的添加,连续煮浆的方法护色效果均显著,其中氯化镁浓度为0.375mg/mL时效果最佳。     

基于镁铝水滑石原位合成制备阻燃纸

考察了利用纤维填充技术在纸浆纤维的细胞腔或细胞壁中原位合成镁铝水滑石制备阻燃纸的可行性及其工艺条件。其方法是向分散开的纤维中加入偏铝酸钠、氢氧化钠、碳酸钠并搅拌,最后加入氯化镁。研究了反应物浓度、反应温度、反应时间等对阻燃纸性能的影响。结果表明,利用纤维填充技术在纸浆纤维中原位合成镁铝水滑石制备阻燃纸是可行的。当镁铝水滑石的沉积率大于25%时,所制备的阻燃纸的氧指数在25%以上,已经达到难燃级。通过对加填后纤维的SEM观察,发现镁铝水滑石在纸浆纤维的表面、壁和腔中均有沉积。     

Extension of Postharvest Life of Oyster Mushroom by Modified Atmosphere Packaging Technique

ABSTRACT: Mushrooms were packaged in polypropylene, low-density polyethylene, linear low-density polyethylene (LLDPE) packages after washing with 0.5% calcium chloride and 0.5% citric acid (CA), and based on off-color and off-odor development, suitable packaging material and washing solution were selected. Effectiveness of magnesium oxide in modifying the in-package gaseous atmosphere and thereby extending the postharvest life was tested by monitoring the physicochemical properties. Oxygen concentration was 5.5% and 9.9% and carbon dioxide concentration was 8.1% and 4.5%, in the control and packages containing 3 g of magnesium oxide, respectively, on day 12 in storage. Packaging mushroom in 0.015 mm LLDPE packages with 3g of magnesium oxide after washing with 0.5% calcium chloride and 0.5% CA was successful in extending the postharvest life at 8°C and 70% RH from 6 d in commercial samples to 12 d.